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 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