Symptoms:

  • Delayed engagement
  • Flare shifts
  • Harsh downshifts
  • Neutral shifts
  • High line pressure
  • Harsh upshifts
  • Wrong gear starts
  • Gear ratio & solenoid codes
  • TCC slip

Cause:

All solenoids are fed by the solenoid regulator valve. Worn valve/bore surfaces allow critical pressurized oil to cross-leak to the sump, reducing available oil pressure and volume for the solenoids. Shift quality will be adversely affected by wear and operating temperatures.

Correction:

Sonnax oversized solenoid pressure regulator valve kit eliminates cross-leaks and loss of critical oil to the sump, restoring correct oil pressure and volume available to the solenoids.

You need this if...

ZF6HP21, ZF6HP28, ZF6HP34 Oversized Solenoid Pressure Regulator Valve Kit Vacuum Test Locations