Tool Required VB-FIX Required

Printpartsummary
Symptoms:
  • Delayed engagement
  • Gear ratio codes
  • High line pressure in Reverse
  • Low pressure
  • 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

Tool Required VB-FIX Required

4T80-E

Oversized Pressure Regulator & Boost Valve Kit

Part No.

72754-03K

Oversized Pressure Regulator & Boost Valve Kit
  • 72754-03k_combo

  • Oversized Pressure Regulator & Boost Valve Kit

Small_72754-03k_combo Small_72754-03k

4T80-E

Oversized Pressure Regulator & Boost Valve Kit

Part No. 72754-03K

  • Spring
  • Pressure Regulator Valve
  • Boost Valve
  • Boost Sleeve

1994 & later

Complaint:

  • Delayed engagement
  • Gear ratio codes
  • High line pressure in Reverse
  • Low pressure
  • 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

  • Hard-coat anodized aluminum valve.
  • New boost valve is calibrated to work with OS pressure regulator valve.
NOTE:

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

Required Tools

You need this if...

Wear is identified by visual inspection or vacuum testing

  • Test Locations

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Contact a Sonnax Distributor to purchase this part.