Symptoms:

  • Delayed engagement
  • Gear ratio codes
  • Low pressure
  • High line pressure in Reverse
  • Repeated case breakage
  • TCC codes

Cause:

Wear at the pressure regulator bore, especially at the balance end, results inthe PR valve not being able to stroke to the lower line pressure position. This results in high line pressure. Leakage of line to exhaust reduces line rise. Slow line rise in response to engine load eventually burns a clutch or reduces TCC apply pressure.

Correction:

Refurbish worn bores using the specially designed F series tool kit and the Sonnax VB- FIX and install the Sonnax oversized Pressure Regulator valve and boost valve assembly

4T80-E

Oversized Pressure Regulator & Boost Valve Kit
Part No. 72754-03K

1994 & later


You need this if... View Instructions Find a Distributor
  • Hard-coat anodized aluminum valve.
  • New boost valve is calibrated to work with OS pressure regulator valve.

Reamer kit F-72754-TL3 is no longer in production but may be available from distributor inventory.

  • Spring
  • Pressure Regulator Valve
  • Boost Valve
  • Boost Sleeve
  • 4T80-E Oversized Pressure Regulator & Boost Valve Kit 72754-03K
  • 4T80-E Oversized Pressure Regulator & Boost Valve Kit 72754-03K

You need this if...

Wear is identified by visual inspection or vacuum testing

4T80-E Oversized Pressure Regulator & Boost Valve Kit Vacuum Test Locations