Symptoms:

  • Delayed Reverse
  • Low line rise in Reverse
  • B2 Clutches burned
  • C3 Clutch burned

Cause:

Continual boost valve stroking results in sleeve bore wear and loss of Reverse pressure.

Correction:

Installing Sonnax boost valve and sleeve restores critical tolerances to bring back normal operating conditions.

TF-80SC, TF-81SC

Boost Valve Kit
Part No. 39741-44K

This kit also fits Volvo (AM6), Opel (AF40), Peugeot (TF80), Saab (AF40/6), Land Rover (TF80), Ford (AF21) and Mazda (AW6A-EL).

You need this if... View Instructions Find a Distributor

In Aisin AW TF-80SC, TF-81SC transmissions, the boost sleeve wears from repeated oscillation of the boost valve, allowing Reverse pressure to exhaust. This can result in delayed Reverse, low line pressure in Reverse and/or burnt C3 and B2 brake clutches. Sonnax boost valve kit 39741-44K eliminates these concerns and restores proper hydraulic control.

  • Valve
  • Sleeve

Sonnax valve body layouts provide a detailed overview of individual units making it quick and easy to determine what’s available for the specific valve body you’re working on. See all Sonnax valve body layouts.

Aisin AW TF-80SC Valve Body Layout

Aisin AW TF-80SC Valve Body Layout

Aisin AW TF-81SC Valve Body Layout

Aisin AW TF-81SC Valve Body Layout
  • TF-80SC, TF-81SC Boost Valve Kit 39741-44K
  • TF-80SC, TF-81SC Boost Valve Kit 39741-44K

You need this if...

A vacuum test at the port indicated fails to hold at least 18 in-Hg.

TF-80SC, TF-81SC Boost Valve Kit Vacuum Test Locations