sonnax-black Facebook-color LinkedIn-color maillink printlink r_and_r_only SERVOFIX-logo-web Twitter-color VBFIX-logo-web video-logo-web warranty_only Youtube-color


  • RPM surge on coast
  • RPM surge on light acceleration
  • Overheated converter fluid
  • Harsh downshifts
  • TCC apply & release concerns
  • TCC codes


Bore wear at the TCC control valve and/or sleeve results in the torque converter clutch remaining applied and transferring the shift shock. Loss of TCC control also results in RPM fluctuation.


The Sonnax oversized lockup control valve and boost assembly kit corrects circuit pressure loss and restores control of the TCC lockup circuit.

55-50SN, 55-51SN

Oversized Lockup Control Valve & Boost Valve Kit
Part No. 59947-29K

Also fits AF 23/33 and RE5F22A units.

You need this if... View Instructions

Bore wear at the lockup control valve in listed units results in loss of torque converter clutch control. The TCC can remain applied transferring shift shock, or loss of lockup control can result in RPM fluctuations. Sonnax oversized lockup control valve and boost valve kit 59947-29K restores control of the TCC. Proper TCC control eliminates the shift shock and RPM fluctuations associated with a worn lockup control valve.

  • Both hardcoat anodized aluminum lockup control valve and boost valve resist wear and fit tighter to the bore than OE for better sealing
  • The boost sleeve is highly wear-resistant to increase life

F-15741-TL29PL is required for securing small No. 2 rear control valve body to VB-FIX.

  • Lockup Control Valve
  • Boost Valve
  • Boost Sleeve
  • Boost 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
  • 59947 29k combo
  • 59947 29k

You need this if...

Vacuum testing at the port(s) indicated fails to hold the recommended minimum in-Hg, or if wear is visually detected.

  • 59947 29k in test