HARSH 1-2 UPSHIFT WHEN HOT 1-2 ACCUM. FEEDBACK ORIFICE

MODELS AFFECTED: 1986 CIMARRON EQUIPPED WITH 125C TRANSAXLE AND 2.0 E.F.I.- L4 ENGINE

1986 Cimarrons equipped with a THM 125C transaxle may experience a harsh 1-2 upshift during a medium to hard acceleration from a standing start after reaching normal transaxle operating temperature.

When servicing a transaxle for this condition, the following must be done.

1. Verify line pressures (see page 125C2) per the 1986 Cimarron Service Information Manual.

2. Verify that intermediate servo piston, seals, pin and bore, are not scored or damaged. Repair as required.

3. Check to assure freedom of movement in the T.V. cable, T.V. plunger, shift T.V. valve and associated parts.

4. Check for proper operation of the 1-2 accumulator valve, piston, springs, inspect for broken seals and damaged bore.

After verifying the above, if the transaxle serial number is within the "Start" - "End" serial number range listed on the chart below (see Figure 1 for transaxle identification information) proceed as follows.

Serial Number Serial Number Spacer Plate Model Start End Part Number ----- ------------- ------------- ------------- CAC 8054 8280 8660581 CBC 127346 128483 8660581 CCC 1914 2059 8660581 CMC 11283 11286 8660581

Remove the spacer plate and measure the diameter of the 1-2 accumulator feedback orifice using a carburetor pin gauge or other suitable measuring tool. (Refer to Figure 2 for location). If the hole is 1.02 mm (0.040 inch), replace the spacer plate with the indicated service spacer plate, which has a larger (3.18 mm/0.125 inc) 1-2 accumulator feedback orifice.

Refer to the appropriate Service Information 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.