CONSISTENT SHIFT POINTS NEW SEALS & PISTONS PART NOS.

VEHICLES AFFECTED: All Models

Beginning June 18, 1986, or julian date 169, (refer to Figure 1) all 1986 THM 700-R4 transmissions are built using new 1-2 and 3-4 accumulator pistons and seals to assist in maintaining consistent shift points and smoothness.

When servicing a 1982 through 1986 THM 700-R4 transmission, use the new pistons and seals (refer to Figure 2) which are available as service package part number 8635909 (one piston and one seal per package). Also, the oil seal is available separately as service part number 8635568.

IMPORTANT: The same design accumulator piston and seal are used in both the 1-2 and 3-4 circuits.

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.