Info - 1-2, 2-3, 3-4, 4-5 Shift and Torque Converter Clutch (TCC) Characteristics During Cold Weather Operation on 4L60-E, 4L80-E or Allison Transmissions
| Subject: | 1-2, 2-3, 3-4, 4-5 Shift and Torque Converter Clutch (TCC) Characteristics During Cold Weather Operation on 4L60-E, 4L80-E or Allison Transmissions |
| Models: | 2002-2004 Cadillac Escalade, Escalade EXT |
| 2003-2004 Cadillac ESV |
| 2001-2004 Chevrolet and GMC Light Duty Full-Size Pickup and Utility Models |
| 2003-2004 HUMMER H2 |
| with 4.3L, 4.8L, 5.3L, 6.0L or 8.1L Gas Engine (VINs W, V, T, N, U, G -- RPOs L35, LR4, LM7, LQ9, LQ4, L18) or 6.6L Diesel Engine (VINs 1, 2 -- RPOs LB7, LLY) |
| and 4L60-E, 4L80-E or Allison Automatic Transmission (RPO M74-Transmission Auto 5-Speed, Allison, LCT 1000, 3.10 1st, 1.00 4th, 0.71 5th, O/D, Conversion Clutch) |
This bulletin is being revised to add model years, model and Allison transmission information. Please discard Corporate Bulletin Number 01-07-30-031 (Section 07 -- Transmission/Transaxle).
Transmission operation during cold weather has been revised on these vehicles to provide faster engine warm-up and improved heater performance. During initial key-up, if the intake air temperature (IAT) is less than -7°C (19°F), 1-2, 2-3 and 3-4 upshift speeds will be affected as detailed below.
Vehicles Equipped with Allison Transmissions
Range Shifts with M74 and L18
No heater performance utilized for range shifts for all model years.
(2001-2004 Model Year) TCC Operation with M74 and L18
If the transmission fluid temperature is less than 18°C (64.4°F), torque converter clutch (TCC) operation will not occur until the transmission fluid temperature is greater than 22°C (71.6°F).
(2001-2004 Model Year) 1-2 Shift with M74 and LB7 or LLY
No heater performance for 1-2 range shift for all model years.
(2001-2004 Model Year) 2-3 Shift with M74 and LB7
If the throttle position (TP) is less than 43 percent, the 2-3 upshift will take place at a minimum speed of 35 km/h (22 mph). This raises the shift point a maximum of 2 mph. If the TP is above 43 percent, the shifts will follow the normal shift pattern. When the transmission sump temperature reaches 44°C (111.2°F), 2-3 upshifts will follow the normal shift pattern.
(2004 Model Year) 2-3 Shift with M74 and LLY
If the throttle position (TP) is less than 37 percent, the 2-3 upshift will take place at a minimum speed of 33 km/h (20 mph). This raises the shift point a maximum of 2 mph. If the TP is above 37 percent, the shifts will follow the normal shift pattern. When the engine coolant temperature reaches 68°C (154.4°F), 2-3 upshifts will follow the normal shift pattern.
(2001-2004 Model Year) 3-4 Shift with M74 and LB7
If the throttle position (TP) is less than 56 percent, the 3-4 upshift will take place at a minimum speed of 52 km/h (32 mph). This raises the shift point a maximum of 5 mph. If the TP is above 56 percent, the shifts will follow the normal shift pattern. When the transmission sump temperature reaches 44°C (111.2°F), 3-4 upshifts will follow the normal shift pattern.
(2004 Model Year) 3-4 Shift with M74 and LLY
If the throttle position (TP) is less than 37 percent, the 3-4 upshift will take place at a minimum speed of 50 km/h (31 mph). This raises the shift point a maximum of 6 mph. If the TP is above 37 percent, the shifts will follow the normal shift pattern. When the engine coolant temperature reaches 68°C (154.4°F), 3-4 upshifts will follow the normal shift pattern.
(2001-2004 Model Year) 4-5 Shift with M74 and LB7
If the throttle position (TP) is less than 56 percent, the 4-5 upshift will take place at a minimum speed of 70 km/h (44 mph). This raises the shift point a maximum of 6 mph. If the TP is above 56 percent, the shifts will follow the normal shift pattern. When the transmission sump temperature reaches 44°C (111.2°F), 4-5 upshifts will follow the normal shift pattern.
(2004 Model Year) 4-5 Shift with M74 and LLY
If the throttle position (TP) is less than 56 percent, the 4-5 upshift will take place at a minimum speed of 67 km/h (42 mph). This raises the shift point a maximum of 6 mph. If the TP is above 56 percent, the shifts will follow the normal shift pattern. When the engine coolant temperature reaches 68°C (154.4°F), 4-5 upshifts will follow the normal shift pattern.
(2001-2004 Model Year) TCC Operation with M74 and LB7 or LLY
If the transmission fluid temperature is less than 29°C (84.2°F), torque converter clutch (TCC) operation will not occur until the transmission fluid temperature is greater than 31°C (87.8°F).
Vehicles Equipped with 4L60-E or 4L80-E Transmissions
1-2 Upshift
If the throttle position (TP) is less than 37 percent, the 1-2 upshift will take place at a minimum speed of 19 km/h (12 mph).
2-3 Upshift
| • | (2001 Model Year) If the throttle position (TP) is less than 37 percent, the 2-3 upshift will take place at a minimum speed of 51 km/h (32 mph). |
| • | (2002-2004 Model Year) If the throttle position (TP) is less than 37 percent, the 2-3 upshift will take place at a minimum speed of 43 km/h (27 mph). |
| • | If the throttle position (TP) is above 37 percent, the shifts will follow the normal shift pattern. |
3-4 Upshift
| • | (2001 Model Year) If the throttle position (TP) is less than 37 percent, the 3-4 upshift will take place at a minimum speed of 75 km/h (47 mph). |
| • | (2002-2004 Model Year) If the throttle position (TP) is less than 37 percent, the 3-4 upshift will take place at a minimum speed of 64 km/h (40 mph). |
| • | If the throttle position (TP) is above 37 percent, the shifts will follow the normal shift pattern. |
TCC Operation
If the transmission fluid temperature is less than 17°C (62.6°F), torque converter clutch (TCC) operation will not occur until the transmission fluid temperature is greater than 20°C (68°F).
(2001 Model Year) When the engine coolant temperature (ECT) reaches 77°C (171°F), 2-3 and 3-4 upshifts will follow the normal shift patterns. A brief description of operation may also be included in the Owner's Manual.
(2002 Model Year) When the ECT reaches 80°C (176°F), 2-3 and 3-4 upshifts will follow the normal shift patterns. A brief description of operation may also be included in the Owner's Manual.
