Symptoms:

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

Cause:

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.

Correction:

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 AF23/33 and RE5F22A units.


You need this if... View Instructions Find a Distributor

In Aisin AW 55-50SN and 55-51SN units, 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.

  • Hardcoat anodized aluminum valves combat premature wear
  • 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, 55-51SN Valve Body Layout

Aisin AW 55-50SN, 55-51SN Valve Body Layout
  • 55-50SN, 55-51SN Oversized Lockup Control Valve & Boost Valve Kit 59947-29K
  • 55-50SN, 55-51SN Oversized Lockup Control Valve & Boost Valve Kit 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.

55-50SN, 55-51SN Oversized Lockup Control Valve & Boost Valve Kit Vacuum Test Locations