TCC ENGAGES IN REVERSE STALLS ENGINE / 200-4R

VEHICLES AFFECTED: 1981-86 THM 200-4R and 700-R4 Transmissions

A 1981 through the current production model year vehicle that uses either a THM 200-4R or THM 700-R4 transmission may have a condition where the engine stops running, or lugs, when shifted from Park/Neutral to Reverse or Drive.

This condition may be a result of torque converter clutch engagement when either gear range is selected, and may be caused by improper operation of the converter clutch valve, located in the pump cover (Refer to Figure 1).

If this conditions exists, inspect the converter clutch apply valve for the following:

Not properly seated or missing retaining ring (item 225). When installing this retaining ring make certain the rounded edge of the ring faces the valve stop (item 226). Refer to Figure 2.

Converter clutch valve (item 227) or valve bore having nicks or burrs.

Missing, broken or damaged converter clutch valve springs (outer spring item 228 and inner spring item 229).

IMPORTANT: Prior to servicing the pump assembly for the above condition, make certain that the engine is properly tuned to specifications.

Refer to the appropriate Service Manual for removal and installation procedures.

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.