NEW DESIGN FORWARD CLUTCH SMOOTHER ENGAGEMENT - ALL 200C

MODELS/YEARS: 1984-87 THM 200C (MV9) EQUIPPED VEHICLES

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 1 and 2) ------------------------- August 4, 1986 (Julian Date 216). These changes were introduced for all THM 200C models:

Forward clutch assembly, minus chock bell in housing (619) Forward clutch piston assembly (623) Additional waved plate (627) Front internal gear (636)

Service Action:

1984-87 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 (629). 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 9 kg (20 lbs.) 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 0.7 mm - 1.5 mm (0.028" - 0.059").

Service Parts Information:

1984-87 models (excluding 1984-85 CZ, JY which are not used by Oldsmobile) 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 211):

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:

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

2. 1987 Service Manual Correction. ------------------------------ The 1987 Cutlass Supreme, Cutlass Salon, Custom Cruiser Chassis Service Manual incorrectly displays the early 1986 type forward clutch. Please make a notation of the new feed/bleed forward clutch usage and reference this bulletin on Automatic Transmission pages 200C-22, 23, 24.

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.