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  • Overheated fluid, bushings & converter
  • High SLT pressure
  • Low SLT pressure
  • Poor shift quality
  • Harsh Reverse
  • TCC slip
  • TCC surge


Bore wear at the spring end of the valve allows the SLT circuit and regulated converter pressure to cross leak. Bore wear at the balance end of the valve reduces converter and lube flow.


Install the Sonnax Secondary Regulator Valve & Spring kit to restore hydraulic integrity to the circuit.

55-50SN, 55-51SN

Oversized Secondary Regulator Valve Kit
Part No. 59947-16K

Also fits AW55-51SN, AF 23/33 and RE5F22A units.

View Instructions
  • Salvages valuable core.
  • Improved valve support to reduce wear.
  • Improved converter feed and lube flow.
  • Anodized aluminum valve replaces OE steel valve for better clearance control with the aluminum casting.
  • Valve
  • Spring

Sonnax valve body layouts provide a detailed overview of individual units making it quick and easy to determine what’s available for the specific valve body you’re working on. See all Sonnax valve body layouts.

Aisin AW 55-50SN Valve Body Layout

Aw55 50sn vbl thumb

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  • 59947 16k combo
  • 59947 16k