TH400, 3L80

Sonnax case saver retainer for the GM TH400 and '98-earlier 4L80-E is the only intermediate clutch retaining ring case saver that allows the intermediate band to be retained. The Sonnax case saver fits over the intermediate band anchor lug inside the case and extends rearward to support the intermediate clutch backing plate retaining ring, preventing case lug blow out. There have been a variety of case saver designs over the years, however all require eliminating the intermediate band as is often done in drag racing trans-brake applications. Only the Sonnax case saver retainer supports the intermediate clutch retaining ring, yet is thin enough to allow the intermediate band to be installed, allowing case lug protection in all applications.

• Protects case lugs from blow out
• Salvages cases with one or two blown lugs
• Use with or without intermediate band

Note:

• See instructions for details on identifying '99-later 4L80-E applications.
• Requires modification to intermediate clutch backing plate.

SONNAX Installation Instructions