TRANSMISSION SLIPS DURING DOWNSHIFTS

VEHICLE APPLICATIONS: 1986-88 RB WITH AUTOMATIC TRANSMISSION

Bulletin Covers:

Some of the subject vehicles may exhibit a momentary engine speed increase of RPM of approximately 50-100 RPMs during a forced downshift. This condition may also be described as slipping of the transmission during the downshift.

This condition may be caused by high servo return spring force counteracting the application force.

Vehicles produced beginning with VIN J7560740 incorporate a lower force spring in the servo unit which addresses this RPM increase/ slip condition.

Corrective action for vehicles exhibiting the described condition is to replace the servo return spring using P/N 94140726 available from CANSPO. The service procedure described in the Service Manual is to be followed when replacing this part.

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.