For 1990-2009 cars

# FOUR SPEED MANUAL TRANSAXLE INSPECTION

WHEN REPAIRING 1980 OR 1981 SKYLARK MANUAL TRANSAXLES FOR EITHER SHIFT FORK WEAR OR AXLE SHAFT SEAL LEAKS DUE TO SIDE GEAR/CASE WEAR, AN INSPECTION SHOULD BE MADE FOR BOTH CONDITIONS TO DETERMINE WHAT THE EXTENT OF REPAIR SHOULD BE.

THE FOLLOWING PROCEDURES SHOULD BE ADHERED TO WHEN MAKING SUCH REPAIRS.

SHIFT FORK WEAR

CONDITIONS OF WORN 76MM TRANSAXLE SHIFT FORKS (BOTH 1-2 AND 3-4) HAVE BEEN FOUND TO BE CAUSED BY THE SHIFT FORK GROOVE SURFACE FINISH IN THE SYNCHRONIZER ASSEMBLY. TO CORRECT A WORN SHIFT FORK CONDITION, REPLACEMENT OF THE 1-2 SYNCHRONIZER ASSEMBLY WITH NEW PART NUMBER 14062629 OR 3-4 SYNCHRONIZER ASSEMBLY WITH NEW PART NUMBER 14062631, TOGETHER WITH THE 1-2 SHIFT FORK, PART NUMBER 14008232 OR THE 3-4 SHIFT FORK, PART NUMBER 14009112, IS MANDATORY.

WHILE THE OLD SYNCHRONIZER ASSEMBLY MIGHT APPEAR TO BE REUSEABLE, THE SHIFT FORK GROOVE IN THE SYNCHRONIZER ASSEMBLY WILL CONTAIN MICROSCOPIC BURRS FROM RUNNING METAL-TO-METAL WITH THE FORK, AND WILL CAUSE CONDITION TO RECUR.

THE NEW SYNCHRONIZER ASSEMBLIES INCORPORATE A SMOOTHER SURFACE IN THE SHIFT FORK GROOVE.

SERVICE OF THE SYNCHRONIZER ASSEMBLY REQUIRES THE REMOVAL OF THE SPEED GEARS FROM THE INPUT OR OUTPUT SHAFTS AS OUTLINED IN THE SERVICE MANUAL

AXLE SHAFT SEAL LEAKS

CONDITIONS OF DRIVE AXLE SEAL LUBE LEAKAGE CAN BE THE RESULT OF THE SIDE GEAR BEING LOOSE IN THE DIFFERENTIAL CASE. THIS CAN RESULT IN AXLE SHAFT MOVEMENT EXCEEDING THE SEAL LIMIT, THEREBY ALLOWING A LEAK.

IF EXAMINATION OF THE SEAL REVEALS NO DISCREPANCIES, SUCH AS WEAR, CUTS, SPLITS, OR IMPROPER INSTALLATION, AND IF THE AXLE SHAFT CAN BE MOVED BY HAND ENOUGH TO PRODUCE AN OIL LEAK, IT IS LIKELY THAT THE SIDE GEAR HAS WORN THE DIFFERENTIAL CASE. TO REPAIR, THE DIFFERENTIAL CASE MUST BE REPLACED, ALONG WITH THE DIFFERENTIAL SIDE GEARS.

INSTALL NEW DIFFERENTIAL CASE (PART NUMBER 463058), SIDE PARTS ( PART NUMBER 14040530) WHICH HAVE IMPROVED FINISH AND NEW THRUST WASHERS (PART NUMBER 14040531) WITH FINE GRAIN PHOSPHATE COATING TO CORRECT THE CONDITION.

WARRANTY INFORMATION

LABOR OPERATION MODEL LABOR TROUBLE OPERATION NUMBER YEAR TIME CODE

SHIFT FORK/ T0093 1980 4.0 HRS 92 SYNCHRONIZER 1981 4.5 HRS

DIFFERENTIAL CASE, T0094 1980 3.2 HRS 92 SIDE GEARS & THRUST WASHERS 1981 3.7 HRS

BOTH SHIFT FORK/ T0095 1980 4.4 HRS. 92 SYNCHRONIZER & DIFFERENTIAL 1981 4.9 HRS. CASE, SIDE GEARS & THRUST WASHERS

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.