Sonnax highlights its heavy-duty intermediate clutch backing plates for GM 4L80-E, 4L85-E and TH400 transmissions. Both backing plates are compatible with OE and aftermarket cases, the company says.
Plates available include:
- Part no. 34144HD-01 (pictured above), .375-in. thick, for 1998 and earlier 4L80-E and TH400 transmissions;
- Part no. 34144HD-02, .275-in. thick, for 1999 and later 4L80-E and 4L85-E transmissions.