INPUT HOUSING AND SHAFT ASSEMBLY SERVICE INFORMATION

MODELS: LIGHT DUTY TRUCKS WITH THM 700-R4 TRANSMISSIONS

Beginning January 26, 1983, all THM 700-R4 transmissions were built with a new input housing and shaft assembly. This new input housing and shaft assembly will have two rows of oil drain holes in the housing with five holes in each row (See Figure No. 1).

This extra row of drain holes will reduce gear clash on four wheel drive vehicles during transfer case shifting. This is a running change on the input housing and shaft assembly and either part can be used for service.

SERVICE INFORMATION

Four scarf cut teflon seals (part number 8642420) are used on the turbine shaft (see Figure No. 1). These seals may be either of three different colors (tan, yellow, orange). The color is only used to identify the manufacturer of the seal and has no effect on service.

Inspect any input housing and shaft assembly received from WDDGM. The front of the turbine shaft must contain a ball check valve and retainer assembly and the rear of the shaft must contain three sealing balls. See Figure No. 2. If these parts are missing from the assembly, return the assembly to WDDGM and obtain the correct part.

The ball check valve and retainer assembly is available as a separate part if required (part number 8647037 for 245 mm converter S/T truck and 8634503 for 298 mm converter C/K truck).

When reassembling an input housing and shaft assembly, be certain to check the input housing to output shaft hp seal for nicks or damage (see Figure No. 2). If this seal is omitted or is damaged it will result in lube starvation to the rear of the transmission.

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.