New Sonnax GM Externally Adjustable Low/Reverse Servo Kits
Checking the rear band adjustment on drag racing GM TH400 and 4L80-E vehicles is critical for keeping the transbrake ready for proper launch, but it’s never been easy to do with OE and most aftermarket-style low/reverse servos.
Featuring a unique design, these two new externally adjustable low/reverse servo kits from Sonnax make it quick and easy for anyone to check and adjust the rear band for improved reliability and consistent, predictable staging.
- Fits TH400: 34914-20K
- Fits 4L80/85-E: 34914-28K
