When servicing any THM 700-R4 transmission for a condition of slipping in reverse or no reverse, be certain to check the reverse input piston for.
1. Damaged lip seals 2. Piston dishing (see Figure No. 1) 3. Piston pad wear
If the reverse input piston has any of the above conditions, replace it.
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.