Sonnax Race-Calibrated Servo Return Spring Kit - SX28133-HD

Mystery band failures in GM Powerglides are a common result of using inconsistent aftermarket servo return springs and weak OE springs prone to collapse. This is a problem that can be traced directly to the pin bias effect. Sonnax race-calibrated servo return spring kit 28133-HD counteracts pin bias effect to ensure consistent servo function for longer band life and a cooler transmission. The spring's higher seat pressure helps ensure full servo release, but also features a lower spring rate to prevent excessive release force in the apply position.

• Specifically designed to work with line pressures from 200-275 psi
• Includes two .050" shims to aid in tuning at higher line pressures
• Works with both OE and aftermarket servo pistons
• Also available in Sonnax supported servo master kit 28821-20K

Contents

• Shims (2)
• Spring