For 1990-2009 cars

# DRIVEN SPROCKET SUPPORT WEAR INFORMATION

WHEN DIAGNOSING A THM 125 TRANSMISSION FOR LACK OF DRIVE, SLIPPING SHIFTS, OR ERRATIC SHIFTS CHECK THE DRIVEN SPROCKET SUPPORT FOR WEAR AS SHOWN IN ILLUSTRATION. THIS WEAR PATTERN, IF PRESENT, IS CAUSED BY THE BEARING SLEEVE ON THE OUTSIDE HUB OF THE DRIVEN SPROCKET MOVING AND WEARING INTO THE DRIVEN SPROCKET SUPPORT. AS THIS WEAR CONDITION REACHES AN ADVANCED STATE THE OIL FEED PASSAGES IN THE DRIVE SPROCKET SUPPORT ARE EXPOSED, ALLOWING AN OIL PRESSURE CROSS LEAK. THE BEARING SLEEVE ON THE DRIVEN SPROCKET MAY, AFTER CAUSING THE DESCRIBED WEAR PATTERN (GROOVE), MOVE BACK TO THE PROPER LOCATION AND APPEAR TO BE NORMAL. CONSEQUENTLY, IF THIS CONDITION IS SUSPECTED, BE CERTAIN TO CHECK THE DRIVEN SPROCKET SUPPORT FOR THE WEAR PATTERN (GROOVE) AS SHOWN IN ILLUSTRATION. IF THE ABOVE CONDITION EXISTS, REPLACE THE DRIVEN SPROCKET, DRIVEN SPROCKET SUPPORT AND ANY OTHER AFFECTED PARTS. CHECK THE DIRECT CLUTCH ASSEMBLY AND INTERMEDIATE BAND FOR WEAR - REPAIR OR REPLACE AS NECESSARY. ALSO, CHECK THE TORQUE CONVERTER AND FLUSH IF REQUIRED.

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.