NEW DESIGN FORWARD CLUTCH SMOOTHER ENGAGEMENT - ALL 200C

1984-87 MODELS EQUIPPED WITH THM 200C (MV9) TRANSMISSION MODELS: All (Excluding 1984-85 CZ, JY)

BULLETIN COVERS:

1987 THM 200C transmissions are being built with a new design "feed/ bleed" system for the forward clutch. This system gives more cushioning during forward clutch apply and can be used on certain past models to reduce a harsh PARK/NEUTRAL to DRIVE engagement feel.

DATE OF PRODUCTION CHANGE: (Figures I And 2) ------------------------- August 4, 1986 (Julian date 216), these changes were introduced for all THM 200C models: Forward clutch assembly, minus check ball in housing (619) Forward clutch piston assembly (623) Additional waved plate (627) Front internal gear (636)

SERVICE ACTION:

1984-1987 MODELS BUILT BEFORE AUGUST 4, 1986 (JULIAN DATE 216):

If a vehicle equipped with a THM 200C transmission listed in SERVICE PARTS INFORMATION has a harsh PARK/NEUTRAL to DRIVE engagement, install the Neutral Drive Shift Package.

1987 MODELS BUILT ON OR AFTER AUGUST 4, 1986 (JULIAN DATE 216):

Models built after implementation of the feed/bleed system can be serviced with individual parts.

IMPORTANT: When servicing the forward clutch, select the correct backing plate (627). Backing plate selection affects piston travel, shift feel and clutch durability.

BACKING PLATE SELECTION (CLUTCH FULLY ASSEMBLED):

Apply an evenly distributed load in the direction indicated in Figure 3 to remove slack from the clutch assembly. Use 20 lbs (9kg) of pressure against the backing plate--excessive pressure will cause an inaccurate measurement. With the clutch assembly compressed, use a feeler gage to measure the distance between the backing plate and snap ring. Correct backing plate travel is 0.7mm-1.5mm (0.028"-O.059").

SERVICE PARTS INFORMATION:

1984-1987 MODELS (EXCLUDING 1984-85 CZ, JY) BUILT BEFORE AUGUST 4, 1986 (JULIAN DATE 216):

PART NUMBER DESCRIPTION ----------- ----------- 8638957 Neutral Drive Shift Package (Contains Forward Clutch Assembly Complete, Front Internal Gear and Thrust Washer) 1987 MODELS BUILT ON OR AFTER AUGUST 4, 1986 (JULIAN DATE 216) : 8648720 Forward Clutch Assembly, Complete 8638956 Forward Clutch Housing Package 8648721 Forward Clutch Piston 8657267 Backing Plate, Selective--Identification 7 (Figure 4) 8657266 Backing Plate, Selective--Identification 6 (Figure 4) 8657618 Backing Plate, Selective--Identification X (Figure 4) 8657265 Backing Plate, Selective--Identification 5 (Figure 4) 8657264 Backing Plate, Selective--Identification 4 (Figure 4) 8639947 Front Internal Gear And Thrust Washer Package

SERVICE NOTES:

Earlier design front internal gears (Service Package Number 8630909) cannot be used with THM 200C models built after August 4, 1986 (Julian date 216).

SERVICE DEPARTMENT PONTIAC DIVISION - GENERAL MOTORS CORPORATION

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.