INTERMITTENT OR COMPLETE LOSS OF DRIVE AND REVERSE

VEHICLES AFFECTED: 1985 - 1986 Models

Some 1985 and 1986 models equipped with a THM440-T4 transaxle may experience either an intermittent or complete loss of drive in all forward and reverse ranges. This condition can be caused by input sprag clutch disengagement or 'pop-out' (refer to the 1985 Service Manual, Section 440-T4, Figure 34, items 650 to 654). Transaxle main line pressures may be uneffected.

When servicing a transaxle for intermittent or complete loss of drive, replace the input sprag clutch assembly. A sprag causing intermittent loss of drive may appear to be in good condition, and should be replaced. Refer to Figures 1 and 2 to ensure proper assembly.

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.