TCC ENGAGES AT WRONG SPEED GREASE/DIRT ON SPEEDO HEAD

If a condition is encountered where the torque converter clutch is engaging at the incorrect speed, be sure to check speedometer head magnet field plate for foreign material i.e.: grease, dirt, etc. Foreign material on the drum could change the signal to the ECM resulting in erratic TCC operation.

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.