Beginning January 9, 1984, all THM 700-R4 transmissions were built with a new Reaction Internal Gear. This new gear has a change in the parking lugs and internal gear teeth area. Since the new gear is dimensionally the same as the former, gear identification marks have been added.
Two types of identification have been used. The first or former being an ink stamp on the top chamfer of the gear (Figure No. 2A). The second or current being a broached line on three parking lugs equally spaced around the internal reaction gear. (See Figures No. 1 and No. 2B). All THM 700-R4 transmissions with a build date of Y4009A,B,C, or H or after will have the new Reaction Internal Gear.
When replacing the Reaction Intemal Gear, order part number 8654161 (new part number).
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.