If your vehicle has a diesel engine, see the DURAMAX® Diesel manual for more information.

Do not tow a trailer during break-in. See New Vehicle Break-In for more information.

Caution: The driver can lose control when pulling a trailer if the correct equipment is not used or the vehicle is not driven properly. For example, if the trailer is too heavy, the brakes may not work well or even at all. The driver and passengers could be seriously injured. The vehicle may also be damaged; the resulting repairs would not be covered by the vehicle warranty. Pull a trailer only if all the steps in this section have been followed. Ask your dealer/retailer for advice and information about towing a trailer with the vehicle.

Notice: Pulling a trailer improperly can damage the vehicle and result in costly repairs not covered by the vehicle warranty. To pull a trailer correctly, follow the advice in this section and see your dealer/retailer for important information about towing a trailer with the vehicle.

To identify the trailering capacity of your vehicle, you should read the information in "Weight of the Trailer" that appears later in this section.

Trailering is different than just driving your vehicle by itself. Trailering means changes in acceleration, braking, handling, durability and fuel economy. Successful, safe trailering takes correct equipment, and it has to be used properly.

That's the reason for this part. In it are many time-tested, important trailering tips and safety rules. Many of these are important for your safety and that of your passengers. So please read this section carefully before you pull a trailer.

If You Do Decide To Pull A Trailer

If you do, here are some important points:

Three important considerations have to do with weight:

Tow/Haul Mode

Press this button at the end of the shift lever to enable/disable the tow/haul mode.

Tow/Haul is a feature that assists when pulling a heavy trailer or a large or heavy load. See Tow/Haul Mode for more information.

Tow/Haul is designed to be most effective when the vehicle and trailer combined weight is at least 75 percent of the vehicle's Gross Combined Weight Rating (GCWR). See "Weight of the Trailer" later in the section. Tow/Haul is most useful under the following driving conditions:

Operating the vehicle in Tow/Haul when lightly loaded or with no trailer at all will not cause damage. However, there is no benefit to the selection of Tow/Haul when the vehicle is unloaded. Such a selection when unloaded may result in unpleasant engine and transmission driving characteristics and reduced fuel economy. Tow/Haul is recommended only when pulling a heavy trailer or a large or heavy load.

Weight of the Trailer

How heavy can a trailer safely be?

It depends on how you plan to use your rig. For example, speed, altitude, road grades, outside temperature and how much your vehicle is used to pull a trailer are all important. It can also depend on any special equipment that you have on your vehicle, and the amount of tongue weight the vehicle can carry. See "Weight of the Trailer Tongue" later in this section for more information.

Maximum trailer weight is calculated assuming only the driver is in the tow vehicle and it has all the required trailering equipment. The weight of additional optional equipment, passengers and cargo in the tow vehicle must be subtracted from the maximum trailer weight.

Use one of the following charts to determine how much your vehicle can weigh, based upon your vehicle model and options.

C-1500 Regular Cab Standard Box (2WD)*	Axle Ratio	Maximum Trailer Weight	GCWR**
4.3L V6	3.23 3.73	4,800 lbs (2 177  kg) 5,300 lbs (2 404  kg)	9,500 lbs (4 309 kg) 10,000 lbs (4 536 kg)
4.8L V8	3.23 3.73	5,200 lbs (2 359 kg) 7,200 lbs (3 266 kg)	10,000 lbs (4 536 kg) 12,000 lbs (5 443 kg)
5.3L V8	3.42 3.73	7,200 lbs (3 266 kg) 8,200 lbs (3 719 kg)	12,000 lbs (5 443 kg) 13,000 lbs (5 897 kg)
*Fifth-wheel or gooseneck kingpin weight 15 percent to 25 percent of trailer weight up to 1,500 lbs (680 kg) maximum. **The Gross Combination Weight Rating (GCWR) is the total allowable weight of the completely loaded vehicle and trailer including any passengers, cargo, equipment and conversions. The GCWR for your vehicle should not be exceeded.

C-1500 Extended Cab Standard Box (2WD)*	Axle Ratio	Maximum Trailer Weight	GCWR**
4.3L V6	3.23 3.73	4,300 lbs (1 950 kg) 4,800 lbs (2 177 kg)	9,500 lbs (4 309 kg) 10,000 lbs (4 536 kg)
4.8L V8	3.23 3.73	4,700 lbs (2 132 kg) 6,700 lbs (3 039 kg)	10,000 lbs (4 536 kg) 12,000 lbs (5 443 kg)
5.3L V8	3.42 3.73	6,700 lbs (3 039 kg) 7,700 lbs (3 493 kg)	12,000 lbs (5 443 kg) 13,000 lbs (5 897 kg)
6.0L V8	3.73	8,800 lbs (3 992 kg)	14,000 lbs (6 350 kg)
6.0L V8+	3.73	10,200 lbs (4 627 kg)	15,500 lbs (7 031 kg)
*Fifth-wheel or gooseneck kingpin weight 15 percent to 25 percent of trailer weight up to 1,500 lbs (680 kg) maximum. **The Gross Combination Weight Rating (GCWR) is the total allowable weight of the completely loaded vehicle and trailer including any passengers, cargo, equipment and conversions. The GCWR for your vehicle should not be exceeded. +NHT Enhanced Trailering Performance Package required.

C-1500 Extended Cab Short Box (2WD)*	Axle Ratio	Maximum Trailer Weight	GCWR**
4.3L V6	3.23 3.73	4,400 lbs (1 196 kg) 4,900 lbs (2 223 kg)	9,500 lbs (4 309 kg) 10,000 lbs (4 536 kg)
4.8L V8	3.23 3.73	4,800 lbs (2 177 kg) 6,800 lbs (3 084 kg)	10,000 lbs (4 536 kg) 12,000 lbs (5 448 kg)
5.3L V8	3.42 3.73	6,800 lbs (3 084 kg) 7,800 lbs (3 538 kg)	12,000 lbs (5 448 kg) 13,000 lbs (5 902 kg)
6.0L V8	3.73	8,800 lbs (3 992 kg)	14,000 lbs (6 350 kg)
*This model is neither designed nor intended to tow fifth-wheel or gooseneck trailers. **The Gross Combination Weight Rating (GCWR) is the total allowable weight of the completely loaded vehicle and trailer including any passengers, cargo, equipment and conversions. The GCWR for your vehicle should not be exceeded.

C-1500 Crew Cab Short Box (2WD)*	Axle Ratio	Maximum Trailer Weight	GCWR**
4.8L V8	3.23 3.73	4,600 lbs (2 086 kg) 6,600 lbs (2 994 kg)	10,000 lbs (4 536 kg) 12,000 lbs (5 443 kg)
5.3L V8	3.42 3.73	6,600 lbs (2 994 kg) 7,600 lbs (3 447 kg)	12,000 lbs (5 443 kg) 13,000 lbs (5 897 kg)
6.0L V8	3.73	8,700 lbs (3 946 kg)	14,000 lbs (6 350 kg)
6.0L V8+	3.73	10,200 lbs (4 627 kg)	15,500 lbs (7 031 kg)
*This model is neither designed nor intended to tow fifth-wheel or gooseneck trailers. **The Gross Combination Weight Rating (GCWR) is the total allowable weight of the completely loaded vehicle and trailer including any passengers, cargo, equipment and conversions. The GCWR for your vehicle should not be exceeded. +NHT Enhanced Trailering Performance Package required.

C-1500 Regular Cab Long Box (2WD)*	Axle Ratio	Maximum Trailer Weight	GCWR**
4.3L V6	3.23 3.73	4,700 lbs (2 132 kg) 5,200 lbs (2 359 kg)	9,500 lbs (4 309 kg) 10,000 lbs (4 536 kg)
4.8L V8	3.23 3.73	5,100 lbs (2 313 kg) 7,100 lbs (3 221 kg)	10,000 lbs (4 536 kg) 12,000 lbs (5 448 kg)
5.3L V8	3.42 3.73	7,000 lbs (3 175 kg) 8,000 lbs (3 629 kg)	12,000 lbs (5 443 kg) 13,000 lbs (5 896 kg)
*Fifth-wheel or gooseneck kingpin weight 15 percent to 25 percent of trailer weight up to 1,500 lbs (680 kg) maximum. **The Gross Combination Weight Rating (GCWR) is the total allowable weight of the completely loaded vehicle and trailer including any passengers, cargo, equipment and conversions. The GCWR for your vehicle should not be exceeded.

C-1500 Extended Cab Long Box (2WD)*	Axle Ratio	Maximum Trailer Weight	GCWR**
5.3L V8	3.42 3.73	6,500 lbs (2 948 kg) 7,500 lbs (3 402 kg)	12,000 lbs (5 443 kg) 13,000 lbs (5 897 kg)
*Fifth-wheel or gooseneck kingpin weight 15 percent to 25 percent of trailer weight up to 1,500 lbs (680 kg) maximum. **The Gross Combination Weight Rating (GCWR) is the total allowable weight of the completely loaded vehicle and trailer including any passengers, cargo, equipment and conversions. The GCWR for your vehicle should not be exceeded.

K-1500 Regular Cab Standard Box (4WD)*	Axle Ratio	Maximum Trailer Weight	GCWR**
4.3L V6	3.73	5,100 lbs (2 313 kg)	10,000 lbs (4 536 kg)
4.8L V8	3.42 4.10	5,900 lbs (2 676 kg) 7,900 lbs (3 583 kg)	11,000 lbs (4 989 kg) 13,000 lbs (5 902 kg)
5.3L V8	3.73 4.10	7,900 lbs (3 583 kg) 8,900 lbs (4 037 kg)	13,000 lbs (5 896 kg) 14,000 lbs (6 350 kg)
*Fifth-wheel or gooseneck kingpin weight 15 percent to 25 percent of trailer weight up to 1,500 lbs (680 kg) maximum. *Fifth-wheel or gooseneck trailer rating limited to 7,300 lbs (3 311 kg). **The Gross Combination Weight Rating (GCWR) is the total allowable weight of the completely loaded vehicle and trailer including any passengers, cargo, equipment and conversions. The GCWR for your vehicle should not be exceeded.

K-1500 Extended Cab Standard Box (4WD)*	Axle Ratio	Maximum Trailer Weight	GCWR**
4.8L V8	3.42 4.10	5,500 lbs (2 495 kg) 7,500 lbs (3 402 kg)	11,000 lbs (4 989 kg) 13,000 lbs (5 897 kg)
5.3L V8	3.73 4.10	7,500 lbs (3 402 kg) 8,500 lbs (3 855 kg)	13,000 lbs (5 897 kg) 14,000 lbs (6 350 kg)
6.0L V8	3.73	8,500 lbs (3 855 kg)	14,000 lbs (6 350 kg)
6.0L V8+	4.10	10,500 lbs (4 763 kg)	16,000 lbs (7 257 kg)
*Fifth-wheel or gooseneck kingpin weight 15 percent to 25 percent of trailer weight up to 1,500 lbs (680 kg) maximum. **The Gross Combination Weight Rating (GCWR) is the total allowable weight of the completely loaded vehicle and trailer including any passengers, cargo, equipment and conversions. The GCWR for your vehicle should not be exceeded. +NHT Enhanced Trailering Performance Package required.

K-1500 Extended Cab Short Box (4WD)*	Axle Ratio	Maximum Trailer Weight	GCWR**
4.8L V8	3.42 4.10	5,500 lbs (2 495 kg) 7,500 lbs (3 402 kg)	11,000 lbs (4 989 kg) 13,000 lbs (5 897 kg)
5.3L V8	3.73 4.10	7,500 lbs (3 402 kg) 8,500 lbs (3 855 kg)	13,000 lbs (5 897 kg) 14,000 lbs (6 350 kg)
6.0L V8	3.73	8,500 lbs (3 856 kg)	14,000 lbs (6 350 kg)
*This model is neither designed nor intended to tow fifth-wheel or gooseneck trailers. **The Gross Combination Weight Rating (GCWR) is the total allowable weight of the completely loaded vehicle and trailer including any passengers, cargo, equipment and conversions. The GCWR for your vehicle should not be exceeded.

K-1500 Crew Cab Short Box (4WD)*	Axle Ratio	Maximum Trailer Weight	GCWR**
4.8L V8	3.42 4.10	5,400 lbs (2 449 kg) 7,400 lbs (3 356 kg)	11,000 lbs (4 989 kg) 13,000 lbs (5 897 kg)
5.3L V8	3.73 4.10	7,500 lbs (3 402 kg) 8,500 lbs (3 855 kg)	13,000 lbs (5 897 kg) 14,000 lbs (6 350 kg)
6.0L V8	3.73	8,400 lbs (3 810 kg)	14,000 lbs (6 350 kg)
6.0L V8+	4.10	10,500 lbs (4 763 kg)	16,000 lbs (7 257 kg)
*This model is neither designed nor intended to tow fifth-wheel or gooseneck trailers. **The Gross Combination Weight Rating (GCWR) is the total allowable weight of the completely loaded vehicle and trailer including any passengers, cargo, equipment and conversions. The GCWR for your vehicle should not be exceeded. +NHT Enhanced Trailering Performance Package required.

K-1500 Regular Cab Long Box (4WD)*	Axle Ratio	Maximum Trailer Weight	GCWR**
4.3L V6	3.73	4,900 lbs (2 223 kg)	10,000 lbs (4 536 kg)
4.8L V8	3.42 4.10	5,900 lbs (2 676 kg) 7,900 lbs (3 583 kg)	11,000 lbs (4 989 kg) 13,000 lbs (5 896 kg)
5.3L V8	3.73 4.10	7,900 lbs (3 583 kg) 8,900 lbs (4 037 kg)	13,000 lbs (5 896 kg) 14,000 lbs (6 350 kg)
*Fifth-wheel or gooseneck kingpin weight 15 percent to 25 percent of trailer weight up to 1,500 lbs (680 kg) maximum. **The Gross Combination Weight Rating (GCWR) is the total allowable weight of the completely loaded vehicle and trailer including any passengers, cargo, equipment and conversions. The GCWR for your vehicle should not be exceeded.

K-1500 Extended Cab Long Box (4WD)*	Axle Ratio	Maximum Trailer Weight	GCWR**
5.3L V8	3.73 4.10	7,300 lbs (3 311 kg) 8,300 lbs (3 765 kg)	13,000 lbs (5 896 kg) 14,000 lbs (6 350 kg)
*Fifth-wheel or gooseneck kingpin weight 15 percent to 25 percent of trailer weight up to 1,500 lbs (680 kg) maximum. **The Gross Combination Weight Rating (GCWR) is the total allowable weight of the completely loaded vehicle and trailer including any passengers, cargo, equipment and conversions. The GCWR for your vehicle should not be exceeded.

C-2500 Extended Cab Standard Box HD (2WD)*	Axle Ratio	Maximum Trailer Weight	GCWR**
6.0L V8	3.73 4.10	10,200 lbs (4 627 kg) 12,700 lbs (5 761 kg)	16,000 lbs (7 257 kg) 18,500 lbs (8 391 kg)
*Fifth-wheel or gooseneck kingpin tongue weight should be 15 percent to 25 percent of trailer weight up to 3,000 lbs (1 361 kg) maximum. *Trailer rating limited to 13,000 lbs (5 897 kg) with weight distributing hitch. **The Gross Combination Weight Rating (GCWR) is the total allowable weight of the completely loaded vehicle and trailer including any passengers, cargo, equipment and conversions. The GCWR for your vehicle should not be exceeded.

C-2500 Crew Cab Standard Box HD (2WD)*	Axle Ratio	Maximum Trailer Weight	GCWR**
6.0L V8	3.73 4.10	10,000 lbs (4 536 kg) 12,500 lbs (5 670 kg)	16,000 lbs (7 257 kg) 18,500 lbs (8 391 kg)
*Fifth-wheel or gooseneck kingpin weight should be 15 percent to 25 percent of trailer weight up to 3,000 lbs (1 361 kg) maximum. *Trailer rating limited to 13,000 lbs (5 897 kg) with weight distributing hitch. **The Gross Combination Weight Rating (GCWR) is the total allowable weight of the completely loaded vehicle and trailer including any passengers, cargo, equipment and conversions. The GCWR for your vehicle should not be exceeded.

C-2500 Regular Cab Long Box HD (2WD)*	Axle Ratio	Maximum Trailer Weight	GCWR**
6.0L V8	3.73 4.10	10,400 lbs (4 717 kg) 12,900 lbs (5 851 kg)	16,000 lbs (7 257 kg) 18,500 lbs (8 391 kg)
*Fifth-wheel or gooseneck kingpin tongue weight should be 15 percent to 25 percent of trailer weight up to 3,000 lbs (1 361 kg) maximum. *Trailer ratings above 13,000 lbs (5 897 kg) require a fifth-wheel or gooseneck hitch. **The Gross Combination Weight Rating (GCWR) is the total allowable weight of the completely loaded vehicle and trailer including any passengers, cargo, equipment and conversions. The GCWR for your vehicle should not be exceeded.

C-2500 Extended Cab Long Box HD (2WD)*	Axle Ratio	Maximum Trailer Weight	GCWR**
6.0L V8	3.73 4.10	10,000 lbs (4 536 kg) 12,500 lbs (5 670 kg)	16,000 lbs (7 257 kg) 18,500 lbs (8 391 kg)
*Fifth-wheel or gooseneck kingpin weight should be 15 percent to 25 percent of trailer weight up to 3,000 lbs (1 361 kg) maximum. *Trailer rating limited to 13,000 lbs (5 897 kg) with weight distributing hitch. **The Gross Combination Weight Rating (GCWR) is the total allowable weight of the completely loaded vehicle and trailer including any passengers, cargo, equipment and conversions. The GCWR for your vehicle should not be exceeded.

C-2500 Crew Cab Long Box HD (2WD)*	Axle Ratio	Maximum Trailer Weight	GCWR**
6.0L V8	3.73 4.10	9,900 lbs (4 490 kg) 12,400 lbs (5 624 kg)	16,000 lbs (7 257 kg) 18,500 lbs (8 391 kg)
*Fifth-wheel or gooseneck kingpin weight should be 15 percent to 25 percent of trailer weight up to 3,000 lbs (1 361 kg) maximum. *Trailer rating limited to 13,000 lbs (5 897 kg) with weight distributing hitch. **The Gross Combination Weight Rating (GCWR) is the total allowable weight of the completely loaded vehicle and trailer including any passengers, cargo, equipment and conversions. The GCWR for your vehicle should not be exceeded.

K-2500 Extended Cab Standard Box HD (4WD)*	Axle Ratio	Maximum Trailer Weight	GCWR**
6.0L V8	3.73 4.10	9,900 lbs (4 490 kg) 12,400 lbs (5 624 kg)	16,000 lbs (7 257 kg) 18,500 lbs (8 391 kg)
*Fifth-wheel or gooseneck kingpin weight should be 15 percent to 25 percent of trailer weight up to 3,000 lbs (1 361 kg) maximum. *Trailer rating limited to 13,000 lbs (5 897 kg) with weight distributing hitch. **The Gross Combination Weight Rating (GCWR) is the total allowable weight of the completely loaded vehicle and trailer including any passengers, cargo, equipment and conversions. The GCWR for your vehicle should not be exceeded.

K-2500 Crew Cab Standard Box HD (4WD)*	Axle Ratio	Maximum Trailer Weight	GCWR**
6.0L V8	3.73 4.10	9,800 lbs (4 445 kg) 12,300 lbs (5 579 kg)	16,000 lbs (7 257 kg) 18,500 lbs (8 391 kg)
*Fifth-wheel or gooseneck kingpin weight should be 15 percent to 25 percent of trailer weight up to 3,000 lbs (1 361 kg) maximum. *Trailer rating limited to 13,000 lbs (5 897 kg) with weight distributing hitch. **The Gross Combination Weight Rating (GCWR) is the total allowable weight of the completely loaded vehicle and trailer including any passengers, cargo, equipment and conversions. The GCWR for your vehicle should not be exceeded.

K-2500 Regular Cab Long Box HD (4WD)*	Axle Ratio	Maximum Trailer Weight	GCWR**
6.0L V8	3.73 4.10	10,200 lbs (4 627 kg) 12,700 lbs (5 761 kg)	16,000 lbs (7 257 kg) 18,500 lbs (8 391 kg)
*Fifth-wheel or gooseneck kingpin weight should be 15 percent to 25 percent of trailer weight up to 3,000 lbs (1 361 kg) maximum. *Trailer rating limited to 13,000 lbs (5 897 kg) with weight distributing hitch. **The Gross Combination Weight Rating (GCWR) is the total allowable weight of the completely loaded vehicle and trailer including any passengers, cargo, equipment and conversions. The GCWR for your vehicle should not be exceeded.

K-2500 Extended Cab Long Box HD (4WD)*	Axle Ratio	Maximum Trailer Weight	GCWR**
6.0L V8	3.73 4.10	9,700 lbs (4 400 kg) 12,200 lbs (5 534 kg)	16,000 lbs (7 257 kg) 18,500 lbs (8 391 kg)
*Fifth-wheel or gooseneck kingpin weight should be 15 percent to 25 percent of trailer weight up to 3,000 lbs (1 361 kg) maximum. *Trailer rating limited to 13,000 lbs (5 897 kg) with weight distributing hitch. **The Gross Combination Weight Rating (GCWR) is the total allowable weight of the completely loaded vehicle and trailer including any passengers, cargo, equipment and conversions. The GCWR for your vehicle should not be exceeded.

K-2500 Crew Cab Long Box HD (4WD)*	Axle Ratio	Maximum Trailer Weight	GCWR**
6.0L V8	3.73 4.10	9,600 lbs (4 354 kg) 12,100 lbs (5 488 kg)	16,000 lbs (7 257 kg) 18,500 lbs (8 391 kg)
*Fifth-wheel or gooseneck kingpin weight should be 15 percent to 25 percent of trailer weight up to 3,000 lbs (1 361 kg) maximum. *Trailer rating limited to 13,000 lbs (5 897 kg) with weight distributing hitch. **The Gross Combination Weight Rating (GCWR) is the total allowable weight of the completely loaded vehicle and trailer including any passengers, cargo, equipment and conversions. The GCWR for your vehicle should not be exceeded.

C-3500 Regular Cab (2WD)*	Axle Ratio	Maximum Trailer Weight	GCWR**
6.0L V8	3.73 4.10	10,100 lbs (4 581 kg) 12,600 lbs (5 715 kg)	16,000 lbs (7 257 kg) 18,500 lbs (8 391 kg)
*Fifth-wheel or gooseneck kingpin weight should be 15 percent to 25 percent of trailer weight up to 3,500 lbs (1 587 kg) maximum. *Trailer rating limited to 13,000 lbs (5 897 kg) with weight distributing hitch. **The Gross Combination Weight Rating (GCWR) is the total allowable weight of the completely loaded vehicle and trailer including any passengers, cargo, equipment and conversions. The GCWR for your vehicle should not be exceeded.

C-3500 Extended Cab (2WD)*	Axle Ratio	Maximum Trailer Weight	GCWR**
6.0L V8	3.73 4.10	9,700 lbs (4 400 kg) 12,200 lbs (5 534 kg)	16,000 lbs (7 257 kg) 18,500 lbs (8 391 kg)
6.0L V8 (Dual Rear Wheels)	3.73 4.10	9,500 lbs (4 309 kg) 12,000 lbs (5 443 kg)	16,000 lbs (7 257 kg) 18,500 lbs (8 391 kg)
*Fifth-wheel or gooseneck kingpin weight should be 15 percent to 25 percent of trailer weight up to 3,500 lbs (1 587 kg) maximum. *Trailer rating limited to 13,000 lbs (5 897 kg) with weight distributing hitch. **The Gross Combination Weight Rating (GCWR) is the total allowable weight of the completely loaded vehicle and trailer including any passengers, cargo, equipment and conversions. The GCWR for your vehicle should not be exceeded.

C-3500 Crew Cab (2WD)*	Axle Ratio	Maximum Trailer Weight	GCWR**
6.0L V8	3.73 4.10	9,600 lbs (4 354 kg) 12,100 lbs (5 488 kg)	16,000 lbs (7 257 kg) 18,500 lbs (8 391 kg)
6.0L V8 (Dual Rear Wheels)	3.73 4.10	9,300 lbs (4 218 kg) 11,800 lbs (5 352 kg)	16,000 lbs (7 257 kg) 18,500 lbs (8 391 kg)
*Fifth-wheel or gooseneck kingpin weight should be 15 percent to 25 percent of trailer weight up to 3,500 lbs (1 587 kg) maximum. *Trailer rating limited to 13,000 lbs (5 897 kg) with weight distributing hitch. **The Gross Combination Weight Rating (GCWR) is the total allowable weight of the completely loaded vehicle and trailer including any passengers, cargo, equipment and conversions. The GCWR for your vehicle should not be exceeded.

K-3500 Regular Cab (4WD)*	Axle Ratio	Maximum Trailer Weight	GCWR**
6.0L V8	3.73 4.10	9,900 lbs (4 490 kg) 12,400 lbs (5 624 kg)	16,000 lbs (7 257 kg) 18,500 lbs (8 391 kg)
6.0L V8 (Dual Rear Wheels)	3.73 4.10	9,700 lbs (4 400 kg) 12,200 lbs (5 534 kg)	16,000 lbs (7 257 kg) 18,500 lbs (8 391 kg)
*Fifth-wheel or gooseneck kingpin weight should be 15 percent to 25 percent of trailer weight up to 3,500 lbs (1 587 kg) maximum. *Trailer rating limited to 13,000 lbs (5 897 kg) with weight distributing hitch. **The Gross Combination Weight Rating (GCWR) is the total allowable weight of the completely loaded vehicle and trailer including any passengers, cargo, equipment and conversions. The GCWR for your vehicle should not be exceeded.

K-3500 Extended Cab (4WD)*	Axle Ratio	Maximum Trailer Weight	GCWR**
6.0L V8	3.73 4.10	9,500 lbs (4 309 kg) 12,000 lbs (5 443 kg)	16,000 lbs (7 257 kg) 18,500 lbs (8 391 kg)
6.0L V8 (Dual Rear Wheels)	3.73 4.10	9,200 lbs (4 173 kg) 11,700 lbs (5 307 kg)	16,000 lbs (7 257 kg) 18,500 lbs (8 391 kg)
*Fifth-wheel or gooseneck kingpin weight should be 15 percent to 25 percent of trailer weight up to 3,500 lbs (1 587 kg) maximum. *Trailer rating limited to 13,000 lbs (5 897 kg) with weight distributing hitch. **The Gross Combination Weight Rating (GCWR) is the total allowable weight of the completely loaded vehicle and trailer including any passengers, cargo, equipment and conversions. The GCWR for your vehicle should not be exceeded.

K-3500 Crew Cab (4WD)*	Axle Ratio	Maximum Trailer Weight	GCWR**
6.0L V8	3.73 4.10	9,300 lbs (4 218 kg) 11,800 lbs (5 352 kg)	16,000 lbs (7 257 kg) 18,500 lbs (8 391 kg)
6.0L V8 (Dual Rear Wheels)	3.73 4.10	9,100 lbs (4 128 kg) 11,600 lbs (5 262 kg)	16,000 lbs (7 257 kg) 18,500 lbs (8 391 kg)
*Fifth-wheel or gooseneck kingpin weight should be 15 percent to 25 percent of trailer weight up to 3,500 lbs (1 587 kg) maximum. *Trailer rating limited to 13,000 lbs (5 897 kg) with weight distributing hitch. **The Gross Combination Weight Rating (GCWR) is the total allowable weight of the completely loaded vehicle and trailer including any passengers, cargo, equipment and conversions. The GCWR for your vehicle should not be exceeded.

Ask your dealer/retailer for our trailering information or advice, or write us at our Customer Assistance Offices. See Customer Assistance Offices for more information.

Weight of the Trailer Tongue

The tongue load (A) of any trailer is an important weight to measure because it affects the total or gross weight of your vehicle. The Gross Vehicle Weight (GVW) includes the curb weight of the vehicle, any cargo you may carry in it, and the people who will be riding in the vehicle. If you have a lot of options, equipment, passengers or cargo in your vehicle, it will reduce the tongue weight your vehicle can carry, which will also reduce the trailer weight your vehicle can tow. And if you will tow a trailer, you must add the tongue load to the GVW because your vehicle will be carrying that weight, too. See Loading the Vehicle for more information about your vehicle's maximum load capacity.

The trailer tongue weight (A) should be 10 percent to 15 percent of the total loaded trailer weight, up to a maximum of 600 lbs (272 kg) for the 1500 or 2500 series, and up to a maximum of 750 lbs (340 kg) for the 2500 HD or 3500 series with a weight carrying hitch. The trailer tongue weight (A) should be 10 percent to 15 percent of the total loaded trailer weight, up to a maximum of 1,000 lbs (453 kg) for the 1500 series and up to a maximum of 1,500 lbs (680 kg) for the 2500, 2500 HD or 3500 series with a weight distributing hitch.

Fifth wheel or gooseneck kingpin weight should be 15 to 25 percent of the trailer weight up to the maximum amount specified in the trailering chart for your vehicle. See "Weight of the Trailer", and "Fifth-Wheel and Gooseneck Trailering" in this section.

Do not exceed the maximum allowable tongue weight for your vehicle. Choose the shortest hitch extension that will position the hitch ball closest to the vehicle. This will help reduce the effect of trailer tongue weight on the rear axle.

After you have loaded the trailer, weigh the trailer and then the tongue separately, to see if the weights are proper. If they are not, you may be able to get them right by moving some items around in the trailer.

Trailering may be limited by the vehicle's ability to carry tongue weight. Tongue weight cannot cause the vehicle to exceed the GVWR (Gross Vehicle Weight Rating) or the RGAWR (Rear Gross Axle Weight Rating). The effect of additional weight may reduce your trailering capacity more than the total of the additional weight.

Consider the following example:

A vehicle model base weight is 5,500 lbs (2 495 kg); 2,800 lbs (1 270 kg) at the front axle and 2,700 lbs (1 225 kg) at the rear axle. It has a GVWR of 7,200 lbs (3 266 kg), a RGAWR of 4,000 lbs (1 814 kg) and a GCWR (Gross Combination Weight Rating) of 14,000 lbs (6 350 kg). The trailer rating should be:

You can expect tongue weight to be at least 10 percent of trailer weight (850 lbs (386 kg)) and because the weight is applied well behind the rear axle, the effect on the rear axle will be greater than just the weight itself, as much as 1.5 times as much. The weight at the rear axle could be 850 lbs (386 kg) X 1.5 = 1,275 lbs (578 kg). Since the rear axle already weighs 2,700 lbs (1 225 kg), adding 1,275 lbs (578 kg) brings the total to 3,975 lbs (1 803 kg). This is very close to, but within the limit for RGAWR as well. The vehicle is set to trailer up to 8,500 lbs (3 856 kg).

But let's say your specific vehicle is equipped with some of the latest options and you have a front seat passenger and two rear seat passengers with some luggage and gear in the vehicle as well. You may add 300 lbs (136 kg) to the front axle weight and 400 lbs (181 kg) to the rear axle weight. Your vehicle now weighs:

Weight is still below 7,200 lbs (3 266 kg) and you may think that you should subtract 700 additional pounds (318 kg) from your trailering capacity to stay within GCWR limits. Your maximum trailer would only be 7,800 lbs (3 538 kg). You may go further and think you must limit tongue weight to less than 1,000 lbs (454 kg) to avoid exceeding GVWR. But, you must still consider the effect on the rear axle. Because your rear axle now weighs 3,100 lbs (1 406 kg), you can only put 900 lbs (408 kg) on the rear axle without exceeding RGAWR. The effect of tongue weight is about 1.5 times the actual weight. Dividing the 900 lbs (408 kg) by 1.5 leaves you with being able to handle only 600 lbs (272 kg) of tongue weight. Since tongue weight is usually at least 10 percent of total loaded trailer weight, you can expect that the largest trailer your vehicle can properly handle is 6,000 lbs (2 721 kg).

It is important that you make sure your vehicle does not exceed any of its ratings -- GCWR, GVWR, RGAWR, Maximum Trailer Rating or Tongue Weight. The only way to be sure you are not exceeding any of these ratings is to weigh your vehicle and trailer.

Total Weight on Your Vehicle's Tires

Be sure your vehicle's tires are inflated to the upper limit for cold tires. You'll find these numbers on the Certification label at the rear edge of the driver's door or see Loading Your Vehicle for more information. Then be sure you don't go over the GVW limit for your vehicle, or the GAWR, including the weight of the trailer tongue. If you use a weight distributing hitch, make sure you don't go over the rear axle limit before you apply the weight distribution spring bars.

Hitches

It's important to have the correct hitch equipment. Crosswinds, large trucks going by and rough roads are a few reasons why you'll need the right hitch.

Weight-Distributing Hitches and Weight Carrying Hitches

A: Body to Ground Distance

B: Front of Vehicle

When using a weight-distributing hitch, the hitch must be adjusted so the distance (A) remains the same both before and after coupling the trailer to the tow vehicle.

If you use a step-bumper hitch, the bumper could be damaged in sharp turns. Make sure there is ample room when turning to avoid contact between the trailer and the bumper.

If you will be pulling a trailer that, when loaded, will weigh more than 5,000 lbs (2 270 kg) be sure to use a properly mounted weight-distributing hitch and sway control of the proper size. This equipment is very important for proper vehicle loading and good handling when driving. Always use a sway control if the trailer will weigh more than these limits. You can ask a hitch dealer about sway controls.

Fifth Wheel and Gooseneck Trailering

Fifth wheel and gooseneck trailers can be used with many pickup models. These trailers place a larger percentage of the weight (kingpin weight) on the tow vehicle than conventional trailers. Make sure this weight does not cause the vehicle to exceed GAWR or GVWR.

Fifth wheel or gooseneck kingpin weight should be 15 to 25 percent of the trailer weight up to the maximum amount specified in the trailering chart for your vehicle. See "Weight of the Trailer" in this section for more information.

The hitch should be located in the pickup bed so that it's centerline is over or slightly in front of the rear axle. Take care that it is not so far forward that it will contact the back of the cab in sharp turns. This is especially important for short box pickups. Trailer pin box extensions and sliding fifth wheel hitch assemblies can help this condition. There should be at least six inches of clearance between the top of the pickup box and the bottom of the trailer shelf that extends over the box.

Make sure the hitch is attached to the tow vehicle frame rails. Do not use the pickup box for support.

Safety Chains

You should always attach chains between your vehicle and your trailer. Cross the safety chains under the tongue of the trailer to help prevent the tongue from contacting the road if it becomes separated from the hitch. Instructions about safety chains may be provided by the hitch manufacturer or by the trailer manufacturer. If you are towing a trailer up to 5,000 lbs (2 271 kg) with a factory-installed step bumper, you may attach the safety chains to the attaching points on the bumper. If you are towing a trailer up to your vehicle's trailer rating limit you may attach the safety chains to the attaching point on the hitch platform. If you are towing with an aftermarket hitch follow the trailer or hitch manufacturer's recommendation for attaching safety chains. Always leave just enough slack so you can turn with your rig. Never allow safety chains to drag on the ground.

Trailer Brakes

If your trailer weighs more than 2,000 lbs (900 kg) loaded, then it needs its own brakes - and they must be adequate. Be sure to read and follow the instructions for the trailer brakes so you'll be able to install, adjust and maintain them properly.

If your vehicle is equipped with StabiliTrak®, your trailer cannot tap into the vehicle's hydraulic brake system.

Your trailer brake system can tap into the vehicle's hydraulic brake system only if:

If everything checks out this far, make the brake tap at the port on the master cylinder that sends the fluid to the rear brakes. But don't use copper tubing for this. If you do, it will bend and finally break off. Use steel brake tubing.

Integrated Trailer Brake Control System

Your vehicle may have an Integrated Trailer Brake Control (ITBC) system for electric trailer brakes.

This symbol is located on the Trailer Brake Control Panel on vehicles with an Integrated Trailer Brake Control System. The power output to the trailer brakes is based on the amount of brake pressure being applied by your vehicle’s brake system. This available power output to the trailer brakes can be adjusted to a wide range of trailering situations.

The ITBC system is integrated with your vehicle’s brake, anti-lock brake and StabiliTrak (if equipped) systems. In trailering conditions that cause your vehicle’s anti-lock brake or StabiliTrak systems to activate, power sent to the trailer's brakes will be automatically adjusted to minimize trailer wheel lock-up. This does not imply that your trailer has the StabiliTrak system.

If your vehicle’s brake, anti-lock brake or StabiliTrak systems are not functioning properly, your ITBC system may not be fully functional or may not function at all. Make sure all of these systems are fully operational to ensure full functionality of the ITBC system.

The ITBC system is powered through your vehicle's electrical system. Turning the ignition off will also turn off the ITBC system. The ITBC system is fully functional only when the ignition is in ON or in RUN.

The ITBC system can only be used with trailers with electric brakes.

Caution: Connecting a trailer that is not compatible with the ITBC system may result in reduced or complete loss of trailer braking. There may be an increase in stopping distance or trailer instability which could result in personal injury or damage to the vehicle, trailer, or other property. An aftermarket controller may be available for use with trailers with surge, air or electric-over-hydraulic trailer brake systems. To determine the type of brakes on the trailer and the availability of controllers, check with your trailer manufacturer or dealer/retailer.

When trailering, make sure of the following:

The ITBC system is a factory installed item. Out-of-factory installation of this system should not be attempted. GM is not responsible for warranty or performance of the system resulting from out-of-factory installation.

Trailer Brake Control Panel

1. Manual Trailer Brake Apply Lever

2. Trailer Gain Adjustment Buttons

The ITBC system has a control panel located on the instrument panel to the left of the steering column. See Instrument Panel Overview for more information on location. The control panel allows you to adjust the amount of output, referred to as trailer gain, available to the electric trailer brakes and allows you to manually apply the trailer brakes. The Trailer Brake Control Panel is used along with the Trailer Brake Display Page on the DIC to adjust and display power output to the trailer brakes.

Trailer Brake DIC Display Page

The ITBC system displays messages into the vehicle’s Driver Information Center (DIC). See DIC Warnings and Messages for more information.

The display page indicates Trailer Gain setting, power output to the electric trailer brakes, trailer connection and system operational status.

1. Trailer Gain Setting

2. Power Output to Trailer Brakes

3. No trailer with electric brakes connected or fault present

The Trailer Brake Display Page can be displayed by performing any of the following actions:

All DIC warning and service messages must first be acknowledged by the driver before the Trailer Brake Display Page can be displayed and Trailer Gain can be adjusted.

TRAILER GAIN - This setting is displayed anytime the Trailer Brake Display Page is active. This setting can be adjusted from 0.0 to 10.0 with either a trailer connected or disconnected. To adjust the Trailer Gain, press one of the Trailer Gain adjustment buttons located on the Trailer Brake Control Panel. Press and hold a gain button to cause the Trailer Gain to continuously adjust. To turn the output to the trailer off, adjust the Trailer Gain setting to 0.0 (zero).

0.0 (zero) gain is the factory default setting. To properly adjust trailer gain, see the Trailer Gain Adjustment Procedure later in this section.

TRAILER OUTPUT - This is displayed any time a trailer with electric brakes is connected. Output to the electric brakes is based on the amount of vehicle braking present and relative to the Trailer Gain setting. Output is displayed from 0 to 10 bars for each gain setting.

The Trailer Output will indicate "- - - - - -" on the Trailer Brake Display Page whenever the following occur:

Manual Trailer Brake Apply

The Manual Trailer Brake Apply Lever is located on the Trailer Brake Control Panel and is used to apply the trailer’s electric brakes independent of your vehicle’s brakes. This lever is used in the Trailer Gain Adjustment Procedure to properly adjust the power output to the trailer brakes. Sliding the lever to the left will apply only the trailer brakes. The power output to the trailer is indicated in the Trailer Brake Display Page in the DIC. If your vehicle’s service brakes are applied while using the Manual Trailer Brake Apply Lever, the trailer output power will be the greater of the two.

The trailer and the vehicle's brake lamps will come on when either vehicle braking or manual trailer brakes are applied.

Trailer Gain Adjustment Procedure

Trailer Gain should be set for a specific trailering condition and must be adjusted any time vehicle loading, trailer loading or road surface conditions change.

Setting the Trailer Gain properly is needed for the best trailer stopping performance. A trailer that is over-gained may result in locked trailer brakes. A trailer that is under-gained may result in not enough trailer braking. Both of these conditions may result in poorer stopping and stability of the vehicle and trailer.

Use the following procedure to correctly adjust Trailer Gain for each towing condition:

1. Make sure the trailer brakes are in proper working condition.
2. Connect a properly loaded trailer to the vehicle and make all necessary mechanical and electrical connections. See Loading the Vehicle for more information.
3. After the electrical connection is made to a trailer equipped with electric brakes:

•	A TRAILER CONNECTED message will be briefly displayed on the DIC display.

•	The Trailer Brake Display Page will appear on the DIC showing TRAILER GAIN and TRAILER OUTPUT.

•	In the Trailer Output display on the DIC, "- - - - - -" will disappear if there is no error present. Connecting a trailer without electric brakes will not clear the six dashed lines.

4. Adjust the Trailer Gain by using the gain adjustment (+ / -) buttons on the Trailer Brake Control Panel.
5. Drive the vehicle with the trailer attached on a level road surface representative of the towing condition and free of traffic at about 20 to 25 mph (32 to 40 km/h) and fully apply the Manual Trailer Brake Apply lever.

Adjusting trailer gain at speeds lower than 20 to 25 mph (32 to 40 km/h) may result in an incorrect gain setting.

6. Adjust the Trailer Gain to just below the point of trailer wheel lock-up, indicated by trailer wheel squeal or puffs of tire smoke when a trailer wheel locks.

Trailer wheel lock-up may not occur if towing a heavily loaded trailer. In this case, adjust the Trailer Gain to the highest allowable setting for the towing condition.

7. Re-adjust Trailer Gain any time vehicle loading, trailer loading or road surface conditions change or if you notice trailer wheel lock-up at any time while you are towing.

Other ITBC Related DIC Messages

In addition to displaying TRAILER GAIN and TRAILER OUTPUT through the DIC, trailer connection and ITBC system status is displayed in the DIC.

TRAILER CONNECTED - This message will be briefly displayed when a trailer with electric brakes is first connected to the vehicle. This message will automatically turn off in about ten seconds. The driver can also acknowledge this message before it automatically turns off.

CHECK TRAILER WIRING - This message will be displayed if:

1. The ITBC system first determines connection to a trailer with electric brakes and then the trailer harness becomes disconnected from the vehicle.

If the disconnect occurs while the vehicle is stationary, this message will automatically turn off in about thirty seconds. This message will also turn off if the driver acknowledges this message off or if the trailer harness is re-connected.

If the disconnect occurs while the vehicle is moving, this message will continue until the ignition is turned off. This message will also turn off if the driver acknowledges this message off or if the trailer harness is re-connected.

2. There is an electrical fault in the wiring to the electric trailer brakes. This message will continue as long as there is an electrical fault in the trailer wiring. This message will also turn off if the driver acknowledges this message off.

To determine if the electrical fault is on the vehicle side or trailer side of the trailer wiring harness connection, do the following:

1. Disconnect the trailer wiring harness from the vehicle.
2. Turn the ignition OFF.
3. Wait ten seconds, then turn the ignition back to RUN.
4. If the CHECK TRAILER WIRING message re-appears, the electrical fault is on the vehicle side.

If the CHECK TRAILER WIRING message only re-appears when you connect the trailer wiring harness to the vehicle, the electrical fault is on the trailer side.

SERVICE TRAILER BRAKE SYSTEM - This message will be displayed when there is a problem with the ITBC system. If this message persists over multiple ignition cycles there is problem with the ITBC system. Take your vehicle to an authorized GM dealer to have the ITBC system diagnosed and repaired.

If either the CHECK TRAILER WIRING or SERVICE TRAILER BRAKE SYSTEM message is displayed while you are driving your vehicle, you no longer have power available to your trailer brakes. When traffic conditions allow, carefully pull your vehicle over to the side of the road and turn the ignition off. Check the wiring connection to the trailer and turn the ignition back on. If either of these messages continues, either your vehicle or your trailer needs service.

An authorized GM dealer may be able to diagnose and repair problems with your trailer. However, any diagnosis and repair of your trailer is not covered under your GM Warranty. Please contact your trailer dealer for assistance with trailer repairs and trailer warranty information.

Driving with a Trailer

Caution: When towing a trailer, exhaust gases may collect at the rear of the vehicle and enter if the liftgate, trunk/hatch, or rear-most window is open.

Engine exhaust contains carbon monoxide (CO) which cannot be seen or smelled. It can cause unconsciousness and even death.

To maximize safety when towing a trailer:

•	Have the exhaust system inspected for leaks and make necessary repairs before starting a trip.

•	Never drive with the liftgate, trunk/hatch, or rear-most window open.

•	Fully open the air outlets on or under the instrument panel.

•	Adjust the Climate Control system to a setting that brings in only outside air and set the fan speed to the highest setting. See Climate Control System in the Index.

For more information about carbon monoxide, see Engine Exhaust .

Towing a trailer requires a certain amount of experience. Before setting out for the open road, you'll want to get to know your rig. Acquaint yourself with the feel of handling and braking with the added weight of the trailer. And always keep in mind that the vehicle you are driving is now a good deal longer and not nearly as responsive as your vehicle is by itself.

Before you start, check all trailer hitch parts and attachments, safety chains, electrical connector, lamps, tires and mirror adjustment. If the trailer has electric brakes, start your vehicle and trailer moving and then apply the trailer brake controller by hand to be sure the brakes are working. This lets you check your electrical connection at the same time.

During your trip, check occasionally to be sure that the load is secure, and that the lamps and any trailer brakes are still working.

While towing a trailer or when exposed to long periods of sunshine, the floor of the truck bed may become very warm. Avoid putting items in the truck bed that might be affected by high ambient temperatures.

Following Distance

Stay at least twice as far behind the vehicle ahead as you would when driving your vehicle without a trailer. This can help you avoid situations that require heavy braking and sudden turns.

Passing

You'll need more passing distance up ahead when you're towing a trailer. And, because you're a good deal longer, you'll need to go much farther beyond the passed vehicle before you can return to your lane.

Backing Up

Hold the bottom of the steering wheel with one hand. Then, to move the trailer to the left, just move that hand to the left. To move the trailer to the right, move your hand to the right. Always back up slowly and, if possible, have someone guide you.

Making Turns

Notice: Making very sharp turns while trailering could cause the trailer to come in contact with the vehicle. The vehicle could be damaged. Avoid making very sharp turns while trailering.

When you're turning with a trailer, make wider turns than normal. Do this so your trailer won't strike soft shoulders, curbs, road signs, trees or other objects. Avoid jerky or sudden maneuvers. Signal well in advance.

Turn Signals When Towing a Trailer

The arrows on your instrument panel will flash whenever you signal a turn or lane change. Properly hooked up, the trailer lamps will also flash, telling other drivers you're about to turn, change lanes or stop.

When towing a trailer, the arrows on your instrument panel will flash for turns even if the bulbs on the trailer are burned out. Thus, you may think drivers behind you are seeing your signal when they are not. It's important to check occasionally to be sure the trailer bulbs are still working.

Driving On Grades

Reduce speed and shift to a lower gear before you start down a long or steep downgrade. If you don't shift down, you might have to use your brakes so much that they would get hot and no longer work well.

You can tow in DRIVE (D). You may want to shift the transmission to lower gear selection if the transmission shifts too often (e.g., under heavy loads and/or hilly conditions).

You may also want to activate the tow/haul mode if the transmission shifts too often. See "Tow/Haul Mode" later in this section.

When towing at high elevation on steep uphill grades, consider the following: Engine coolant at higher elevations will boil at a lower temperature than at or near sea level. If you turn your engine off immediately after towing at high elevation on steep uphill grades, your vehicle may show signs similar to engine overheating. To avoid this, let the engine run while parked, preferably on level ground, with the transmission in PARK (P) at least five minutes before turning the engine off. If you do get the overheat warning, see Engine Overheating .

Parking on Hills

Caution: Parking the vehicle on a hill with the trailer attached can be dangerous. If something goes wrong, the rig could start to move. People can be injured, and both the vehicle and the trailer can be damaged. When possible, always park the rig on a flat surface.

But if you ever have to park your rig on a hill, here's how to do it:

1. Apply your regular brakes, but don't shift into PARK (P) yet.
2. Have someone place chocks under the trailer wheels.
3. When the wheel chocks are in place, release the regular brakes until the chocks absorb the load.
4. Reapply the regular brakes. Then apply your parking brake and shift into PARK (P).
5. If you have a four-wheel-drive vehicle, be sure the transfer case is in a drive gear and not in NEUTRAL.
6. Release the regular brakes.

Caution: It can be dangerous to get out of the vehicle if the shift lever is not fully in P (Park) with the parking brake firmly set. The vehicle can roll.

If the engine has been left running, the vehicle can move suddenly. You or others could be injured. To be sure the vehicle will not move, even when on fairly level ground, use the steps that follow.

Always put the shift lever fully in P (Park) with the parking brake firmly set.

If the transfer case on a four-wheel-drive vehicle is in N (Neutral), the vehicle will be free to roll, even if the shift lever is in P (Park). Be sure the transfer case is in a drive gear -- not in N (Neutral).

When You Are Ready to Leave After Parking on a Hill

1. Apply your regular brakes and hold the pedal down while you:

•	Start your engine

•	Shift into a gear

•	Release the parking brake

2. Let up on the brake pedal.
3. Drive slowly until the trailer is clear of the chocks.
4. Stop and have someone pick up and store the chocks.

Maintenance When Trailer Towing

Your vehicle will need service more often when you're pulling a trailer. See Scheduled Maintenance for more information. Things that are especially important in trailer operation are automatic transmission fluid (don't overfill), engine oil, axle lubricant, belt, cooling system and brake system. Each of these is covered in this manual, and the Index will help you find them quickly. If you're trailering, it's a good idea to review these sections before you start your trip.

Check periodically to see that all hitch nuts and bolts are tight.

Trailer Wiring Harness

Your vehicle is equipped with one of the following wiring harnesses for towing a trailer or hauling a slide-in camper.

Basic Trailer Wiring

All regular, extended cab and crew cab pickups have a seven-wire trailer towing harness.

For vehicles not equipped with heavy duty trailering, the harness is clipped to the vehicle's frame behind the spare tire mount. The harness requires the installation of a trailer connector, which is available through your dealer.

If you need to tow a light-duty trailer with a standard four-way round pin connector, you can also get an adapter from your dealer.

Heavy-Duty Trailer Wiring Harness Package

For vehicles equipped with heavy duty trailering, the harness is connected to a bracket on the hitch platform. The seven-wire harness contains the following trailer circuits:

*The fuses for these two circuits are installed in the underhood electrical center, but the wires are not connected. They should be connected by your dealer or a qualified service center. The fuse and wire for the ITBC is factory installed and connected if the vehicle is equipped with an ITBC. The fuse for the battery feed is not required if your vehicle has an auxiliary battery. If your vehicle does not have an auxiliary battery, have your dealer or authorized service center install the required fuse.

If you are charging a remote (non-vehicle) battery, press the tow/haul mode button located at the end of the shift lever. This will boost the vehicle system voltage and properly charge the battery. If the trailer is too light for tow/haul mode, you can turn on the headlamps as a second way to boost the vehicle system and charge the battery.

Camper/Fifth-Wheel Trailer Wiring Package

The seven-wire camper harness is located under the front edge of the pickup box on the driver's side of the vehicle, attached to the frame bracket. A connector will have to be added to the wiring harness which connects to the camper.

The harness contains the following camper/trailer circuits:

If your vehicle is equipped with the "Heavy-Duty Trailering" option, please refer to "Heavy-Duty Trailer Wiring Package" earlier in this section.

When the camper-wiring harness is ordered without the heavy-duty trailering package, an eight-wire harness with a seven-pin connector is located at the rear of the vehicle and is tied to the vehicle's frame.

Electric Brake Control Wiring Provisions

These wiring provisions are included with your vehicle as part of the trailer wiring package. These provisions are for an electric brake controller. The instrument panel contains blunt cut wires near the data link connector for the trailer brake controller. The harness contains the following wires:

It should be installed by your dealer or a qualified service center.

If your vehicle is equipped with an ITBC, the blunt cuts exist, but are not connected further in the harness. If you install an aftermarket trailer brake controller, the ITBC must be disconnected. Do not power both ITBC and aftermarket controllers to control the trailer brakes at the same time.

Auxiliary Battery

The auxiliary battery provision can be used to supply electrical power to additional equipment that you may choose to add, such as a slide-in camper. If your vehicle has this provision, this relay will be located on the driver's side of the vehicle, next to the underhood electrical center.

Be sure to follow the proper installation instructions that are included with any electrical equipment that you install.

Notice: Leaving electrical equipment on for extended periods will drain the battery. Always turn off electrical equipment when not in use and do not use equipment that exceeds the maximum amperage rating for the auxiliary battery provision.

When towing at high elevation on steep uphill grades, consider the following:

Engine coolant at higher elevation will boil at a lower temperature than at or near sea level. If the engine is turned off immediately after towing at high elevation on steep uphill grades, the vehicle may show signs similar to engine overheating. To avoid this, let the engine run while parked (preferably on level ground) with the transmission in P (Park) and the park brake applied for at least five minutes before turning the engine off. If the overheat warning comes on, see Engine Overheating.

Use one of the following charts to determine how much the vehicle can weigh, based upon your vehicle model and options.

Vehicle	Axle Ratio	Max. Trailer Wt.	GCWR**
C-2500 Extended Cab Standard Box HD -- 2WD*†	3.73	15,400 lbs (6 985 kg)	22,000 lbs (9 979 kg)
C-2500 Crew Cab Standard Box HD -- 2WD*†	3.73	15,200 lbs (6 895 kg)	22,000 lbs (9 979 kg)
C-2500 Regular Cab Long Box HD -- 2WD*†	3.73	15,800 lbs (7 167 kg)	22,000 lbs (9 979 kg)
C-2500 Extended Cab Long Box HD -- 2WD*†	3.73	15,000 lbs (6 804 kg)	22,000 lbs (9 979 kg)
C-2500 Crew Cab Long Box HD -- 2WD*†	3.73	14,400 lbs (6 532 kg)	22,000 lbs (9 979 kg)
K-2500 Extended Cab Standard Box HD -- 4WD*†	3.73	14,300 lbs (6 486 kg)	22,000 lbs (9 979 kg)
K-2500 Crew Cab Standard Box HD -- 4WD*†	3.73	13,600 lbs (6 169 kg)	22,000 lbs (9 979 kg)
K-2500 Regular Cab Long Box HD -- 4WD*†	3.73	15,500 lbs (7 031 kg)	22,000 lbs (9 979 kg)
K-2500 Extended Cab Long Box HD -- 4WD*†	3.73	13,400 lbs (6 078 kg)	22,000 lbs (9 979 kg)
K-2500 Crew Cab Long Box HD -- 4WD*†	3.73	12,500 lbs (5 670 kg)	22,000 lbs (9 979 kg)
C-3500 Extended Cab -- 2WD*†
Single Rear Wheels	3.73	15,100 lbs (6 849 kg)	22,000 lbs (9 979 kg)
Dual Rear Wheels	3.73	16,300 lbs (7 393 kg)	23,500 lbs (10 659 kg)
C-3500 Crew Cab -- 2WD*†
Single Rear Wheels	3.73	14,900 lbs (6 758 kg)	22,000 lbs (9 979 kg)
Dual Rear Wheels	3.73	16,200 lbs (7 348 kg)	23,500 lbs (10 659 kg)
K-3500 Regular Cab -- 4WD*†
Single Rear Wheels	3.73	15,300 lbs (6 940 kg)	22,000 lbs (9 979 kg)
Dual Rear Wheels	3.73	16,500 lbs (7 484 kg)	23,500 lbs (10 659 kg)
K-3500 Extended Cab -- 4WD*†
Single Rear Wheels	3.73	14,900 lbs (6 758 kg)	22,000 lbs (9 979 kg)
Dual Rear Wheels	3.73	16,000 lbs (7 257 kg)	23,500 lbs (10 659 kg)
K-3500 Crew Cab -- 4WD*†
Single Rear Wheels	3.73	14,600 lbs (6 622 kg)	22,000 lbs (9 979 kg)
Dual Rear Wheels	3.73	15,900 lbs (7 212 kg)	23,500 lbs (10 659 kg)
G2500 Cargo Van Short Wheelbase -- 2WD	3.73	10,000 lbs (4 536 kg)	17,000 lbs (7 711 kg)
G2500 Cargo Van Long Wheelbase -- 2WD	3.73	10,000 lbs (4 536 kg)	17,000 lbs (7 711 kg)
G3500 Cargo Van Short Wheelbase -- 2WD	3.73	10,000 lbs (4 536 kg)	17,000 lbs (7 711 kg)
G3500 Cargo Van Long Wheelbase -- 2WD	3.73	10,000 lbs (4 536 kg)	18,500 lbs (8 391 kg)
G3500 Passenger Van Short Wheelbase -- 2WD	3.73	10,000 lbs (4 536 kg)	17,000 lbs (7 711 kg)
*Fifth-wheel or gooseneck kingpin weight should be 15 percent to 25 percent of trailer weight up to 3,500 lbs (1 587 kg) maximum. †Trailer rating limited to 13,000 lbs (5 897 kg) with weight distributing hitch. **The Gross Combination Weight Rating (GCWR) is the total allowable weight of the completely loaded vehicle and trailer including any passengers, cargo, equipment and conversions. The GCWR for the vehicle should not be exceeded.

See "Towing a Trailer" in the Index of the vehicle's owner manual for more information.