Symptoms:

  • No lockup
  • No TCC release
  • Engine stall
  • TCC codes
  • Excess TCC slip
  • Premature TCC apply
  • Soft TCC apply
  • Harsh TCC apply

Cause:

Bore wear at the TC switch valve allows pressure loss that leads to drivability concerns.

Correction:

Recover hydraulic control and renew TCC performance by reconditioning the bore and installing Sonnax oversized TC switch valve.

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.

845RE, ZF8HP45, ZF8HP55, ZF8HP70 Oversized TC Switch Valve Vacuum Test Locations