A/T - Harsh Park/Neutral Drive Engagement
SUBJECT NEW DESIGN FORWARD CLUTCH FOR NUMBER: 87-T-26SMOOTHER PARK/NEUTRAL TO DRIVE ENGAGEMENT
DATE: June 9, 1987
MODELS/YEARS 1984-87 THM 200C (MV9) EQUIPPED
VEHICLES SECTION: 7A
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.
FIGURE 1 - THM 200C TRANSMISSION NAMEPLATE:
FIGURE 2:
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 check ball 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.
FIGURE 3:
Backing Plate Selection (Clutch Fully Assemblied):
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 gauge 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 216):
8648720 Forward clutch assembly, complete
8638956 Forward clutch housing package
8648721 Forward clutch piston
FIGURE 4:
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 20OC-22, 23, 24.