Beginning September 1, 1983, all THM 700-R4 transmissions were built with a revised design snap ring for both the reaction sun gear and the lo and reverse spring retainer to case. (See Figure No. 1).
When disassembling or inspecting any THM 700-R4 transmission, it is not necessary to remove the snap ring from the reaction sun gear unless you intend to replace it.
When servicing any THM 700-R4 transmission reaction sun gear or lo and reverse spring retainer to case snap ring, replace it with P/N 8647337. When installing the snap ring, DO NOT over expand 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.