For 1990-2009 cars

# NEW DESIGN FORWARD CLUTCH SMOOTHER PK./NEUT. TO DRIVE

#### MODELS/YEARS: 1981-87 THM 200-4R EQUIPPED VEHICLES

#### Bulletin Covers:

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) ------------------------- April 25, 1986 (Julian Date 115), the following changes were introduced for all THM 220-4R models (excluding 1986 BRF, which is not used by Oldsmobile).

Forward clutch assembly, minus check ball in housing (618) Forward clutch piston assembly (622) Additional waved plate (666) Front internal gear (633)

#### Service Action:

#### 1981-86 models built prior to April 25, 1986 (Julian Date 115):

If a vehicle equipped with a THM 200-4R transmission built prior to April 25, 1986 (Julian Date 115) exhibits a harsh park/neutral to drive engagement, install the service package listed in service parts information.

#### NOTICE: This system cannot be used on 1986-87 BRF, 1984-85 BQ and 1983 BR (which are not used by Oldsmobile)

#### 1986-87 models built on or after April 25, 1986 (Julian Date 115):

#### 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 9 kg (20 lbs.) of presure 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"). Refer to Figure 4 for backing plate identification information.

#### Service Part Information:

8639943 Neutral drive shift package (contains forward clutch) assembly complete, front internal gear and thrust washer):

For models built on or after April 25, 1986, (Julian Date 115), refer to the current GMSPO catalog for separately available part numbers.

#### Service Notes:

1. Earlier design front internal gears (service package number 8630909) cannot be used with THM 200-4R models built after April 25, 1986 (Julian Date 115).

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 used and reference this bulletin, on Automatic Transmission pages 200-4R-12, 27 and 28 of this manual.

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.