New Backing Plate and Snap Ring For 2ND Clutch Pack

SUBJECT:

NEW BACKING PLATE AND SNAP RING FOR 2nd CLUTCH PACK

FIGURE 11 - 2ND CLUTCH REVISED BACKING PLATE:

CHANGE TO ASSEMBLY COMPONENTS: (Figure 11)

A new shorter 2nd clutch backing plate that eliminates the groove and cutouts for the snap ring, replaces the previous 2nd clutch backing plate and snap ring. A new snap ring that is about half as wide as the previous model year must be used with the new backing plate.

DATE OF PRODUCTION CHANGE:

The THM F-7 started using the new backing plate and snap ring at Start Of Production (SOP) 1989.

The THM 440-T4 started using the new backing plate and snap ring on August 22, 1988 (Julian Date 235).

SERVICE ACTION:

DO NOT service the new backing plate (619) and snap ring (620) into a prior year 2nd clutch. This may cause the backing plate to crack if the new 2nd clutch backing plate is used with the old (non chamfered) reaction drum and/or an engine without torque management.

SERVICE PARTS INFORMATION:

Part Model Model
Number Description Year Usage

8668566 Plate, Backing Support Ring 1989 All

8668567 Ring, Snap 1989 All

8662010 Plate, Backing Support Ring 1987-88 All

8661141 Ring, Snap 1987-88 All

Part numbers 8668566 and 8668567 are expected to be available on November 21, 1988. Until then normal part orders will not be accepted by GMSPO. Only verifiable emergency VIP orders will be accepted. GMSPO will make every effort to obtain parts. All parts will be placed on 400 control to waive VIP surcharges. However, the part will be shipped premium transportation at dealer's expense. All other order types will be cancelled as incorrectly ordered while the 400 control is in place.

Part numbers 8662010 and 8661141 are currently available from GMSPO.

SERVICE MANUAL REFERENCE:

This product change does not affect diagnosis for 1989 THM 440-T4 transaxles and is not shown in the 1989 THM 440-T4 Unit Repair Section of your Service Manual.