Race-Calibrated Servo Return Spring Kit

Race-Calibrated Servo Return Spring Kit  [28133-HD]

Condition: New.

Availability: In stock, usually ships within 1 to 3 days.

Price: $11.71 / Ea

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.

  • Counteracts pin bias effect up to 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 servo kit 28821-20K
  • Shims (2)
  • Spring

Instructions Instructions

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