C 1500 Truck 2WD V8-454 7.4L (1990)
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 available at GMSPO.
Service Manual Reference:
Refer to the HYDRA-MATIC 4L60 Automatic Transmission Unit Repair Section of the appropriate Service Manual for instructions on installing the
reverse input clutch seals.