PARTS UPDATE-HARSH PARK OR NEUTRAL TO REVERSE ENGAGEMENT

TRANSMISSION APPLICATIONS: SUBJECT:

1987-88 THM 200-4R (MW9) SERVICE PARTS UPDATE - HARSH PARK OR NEUTRAL TO REVERSE ENGAGEMENT

TRANSMISSION MODELS: VEHICLE APPLICATIONS:

7CCF,7CHF,7CRF,7CTF,7CYF 1987-88 B, D, G -CARS AND W TRUCKS 7CZF,7KJF,7KTF,8CCF,8CHF 8CRF,8CTF,8CYF,8CZF,8KTF

Bulletin Covers:

(Revised to Correct Figures)

Service parts for a 1987 or 1988 THM 200-4R transmission exhibiting a harsh Park or Neutral to Reverse engagement. The "reverse engagement package," a new spacer plate and 1-2 accumulator housing assembly are available for service. The spacer plate and accumulator housing function as a Reverse accumulator to soften Reverse engagement.

DATE OF PRODUCTION CHANGE: (Figure 1) ------------------------- All THM 200-4R models built after March 14, 1988 (Julian date 074), were built with the new Spacer Plate and 1-2 Accumulator Housing Assembly.

SERVICE PROCEDURE: (Figure 2) ------------------ To service a 1987 or 1988 THM 200-4R CCF, CHF, CRF, CTF, CYF, CZF, KCF, KJF, KTF model exhibiting a harsh reverse engagement (built prior to March 14, 1988), replace the spacer plate and 1-2 accumulator housing assembly with the appropriate parts listed under "Service Parts Information".

To identify the "reverse engagement" spacer plate and 1-2 accumulator housing:

The new spacer plate has a round hole (indicated by the arrow in Figure 3); the previous spacer plate had a rectangular hole in that location.

The new 1-2 accumulator housing contains a checkball and sleeve assembly (refer to Figure 4).

SERVICE PARTS INFORMATION:

Part Number Description Model ----------- ----------- ----- 8657755 1-2 Accumulator Housing Assembly 7CCF,7CHF,7CRF,7CTF 8634969 Spacer Plate Gaskets (Pkg. of 2) 7CYF,7CZF,7KJF,7KTF 8634166 1-2 Accumulator Housing to 8CCF,8CHF,8CRF,8CTF Accumulator Plate Gasket 8CYF,8CZF,8KTF

8669050 Spacer Plate (Identification: CD) 7CRF,7CTF,8CRF,8CTF

8669060 Spacer Plate (Identification: CH) 7KJF,7KTF,8KTF

8669051 Spacer Plate (Identification: CE) 7CCF, 8CCF

8669049 Spacer Plate (Identification: CC) 7CHF, 8CHF

8669052 Spacer Plate (Identification: CF) 7CYF, 8CYF

8669047 Spacer Plate (Identification: CA) 7CZF, 8CZF

Parts are currently available from CANSPO.

Transmissions built after implementation of the reverse engagement package, March 14, 1988, can be serviced with individual components. Refer to the Parts catalogue for part numbers.

SERVICE MANUAL REFERENCE:

Refer to the Unit Repair section of the THM 200-4R service manual for spacer plate and 1-2 accumulator service information.

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.