A/T - No Reverse/Delayed Reverse Cold

9217buick06

Bulletin 91-74L60-1

Date Mar. '92

Ref. No. 91-297-74L60

Corp. Ref. No. 277111


SUBJECT:
NO REVERSE/DELAYED REVERSE COLD (INSTALL LONG LIPPED REVERSE INPUT CLUTCH PISTON OUTER SEAL)

MODELS AFFECTED:
1991 ROADMASTER


Some 1991 Roadmasters may exhibit a "no reverse" or "delayed reverse" condition when outside temperatures are below zero degrees Fahrenheit.

SERVICE INFORMATION:

A transmission is considered to have a delayed reverse condition if it takes longer than three seconds for the transmission to engage when shifted into the reverse range.





If a transmission has a "no reverse" or "delayed reverse" condition, inspect the reverse input clutch piston outer seal. Determine if the seal is a "short lip" or "long lip" design by comparing it to Figure 1. If it is a short lip design, replace it with a long lip seal contained in the service packages listed under Service Parts Information.

If the reverse input clutch piston outer seal is a long lip design, or the newly installed long lip seal doesn't alleviate the delayed reverse condition, the reverse input clutch housing may be out of round. Inspect the housing and replace if necessary.

SERVICE PARTS INFORMATION:

The long lipped seals are available in several service packages.

Description Part Number
Pkg - Overhaul Seals and Gaskets 8683958
Pkg - Overhaul Repair Complete 8683959

Parts are currently available from GMSPO.

SERVICE MANUAL REFERENCE:

Refer to the HYDRA-MATIC 4L60 Automatic Transmission Unit Repair Section of the Roadmaster Service Manual for instructions on installing the reverse input clutch seals.