DIFFERENTIAL CASE PINION BROKEN PINION SHAFT LOCK SCREW

MODELS: S/T TRUCK & C/K/G MODELS W/8.50 INCH RING GEAR AXLE

The following procedure should be used to remove a broken differential pinion cross shaft lock screw. SAFETY GLASSES MUST BE WORN.

STANDARD DIFFERENTIAL

1. Install puller J-22888 or equivalent with the puller jaws inserted into the care openings and puller screw against the end of the pinion cross shaft on the side of the case opposite the lock screw. Refer to Figure No. 1. This is necessary so shearing the lock screw will not distress the pinion gear surface inside thc case. A spacer such as a 5/16" nut may be required between the puller screw and the pinion cross shaft.

2. Position the case assembly on an angle so pinion cross shaft will clear pinion gear head during removal procedure.

3. Tighten puller screw to 50-55 lbs. ft. (68-75 N.m). Tap end of puller once with a hammer. Retighten puller screw about 1/8 turn (50-55 lbs. ft. (68-75 N.m) and tap again. Repeat procedure until pinion cross shaft shears the lock screw.

NOTICE: Too severe of a hammer blow may damage carrier side bearings.

4. When the lock screw is sheared, remove puller, turn case assembly and remove pinion cross shaft. The remainder of the lock screw can then usually be removed with a prick punch. A slight metal distress from lock screw hole to outer portion of case is acceptable. If case is broken out at lock screw hole area, the case must be replaced.

5. Install new parts as required and reassemble differential.

LIMITED SLIP DIFFERENTIAL

A limited slip differential case assembly does not have access for both puller jaws.

As the lock screw hole in the pinion cross shaft is within .150" from the end of the shaft, a die grinder with a 1/4" carbide bit can be used to grind a groove through the end of the pinion cross shaf exposing the lock screw. A 1/4" die grinder is a commonly available 28,000 to 30,000 RPM tool similay to a router. Both electric and air powered die grinders are available from power tool sources. This tool and bit is also useful for elongating holes in steel, etc.

1. Wrap the ring gear in a shop towel and place towels around case assembly exposing only the end of pinion cross shaft. This will protect the differential internal parts from exposure to metal grindings. Refer to Figure No. 2.

2. Inspect and correct any fuel leaks in area of tank and fuel lines, as grinder will cause sparks.

3. Grind a groove through the end of the pinion cross shaft exposing the lock screw. When lock screw is exposed, use a punch and hammer to drive out pinion cross shaft past the lock screw with the case on an angle so shaft will clear pinion gear head.

4. In most instances, the broken piece of lock screw can be removed with the case still in the housing.

5. Clean all traces of grindings from housing.

6. Install new parts as required and reassemble differential.

General Motors bulletins are intended for use by professional technicians, not a "do-it-yourselfer". They are written to inform those technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions and know-how to do a job properly and safely. If a condition is described, do not assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See a General Motors dealer servicing your brand of General Motors vehicle for information on whether your vehicle may benefit from the information.