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Sonnax 28821-20K Supported Servo Master Kit Everything Needed For The Powerglide
$ 60.48
- Description
- Size Guide
Description
PowerglideSupported Servo Master Kit
Part No.
28821-20K
Conventional GM Powerglide servos are not well-supported and the return springs do not function properly, both leading causes of band failure. Sonnax supported servo master kit 28821-20K is an all-in-one kit that eliminates piston binding and includes a race-calibrated spring to counteract the pin bias effect.
At high apply pressures or with a worn servo pin bore, the servo piston is side-loaded in the case, causing friction and binding of the piston. The supported pin design of this Sonnax kit eliminates friction caused by side-loading and ensures the servo piston will apply and release without binding.
"Mystery" band failures are a common result of aftermarket servo return springs and weak OE springs prone to collapse that do not reliably release the servo. The Sonnax spring in this kit is race-calibrated 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.
Unique cover and pin combination eliminates piston binding that causes unexplained band failure
Race-calibrated spring counteracts pin bias effect up to 275 psi
Dual PTFE seal rings for better seal and low friction
OE apply area
Low-profile design ensures adequate clearance
6061 Anodized billet aluminum cover
Contents
Supported Servo Cover
Supported Servo Pin
Servo Piston
Return Spring
Retaining Clip
Gasket
Cover O-Ring
Pin O-Rings (2)
1 extra
Drain Plug
Not shown
Bolts (3)
Not shown
Pin Shims (3)
Spring Shims (2)
PTFE Piston Seal Rings (2)