Wear at the 1-2 accumulator valve and/or bore, allowing loss of torque signal, 1-2 accumulator and/or line pressure.
Refurbish the worn bore and install the Sonnax oversized valve to restore correct hydraulic clearances.
Required tool kit F-84754-TL57 is no longer in production. Check with your distributor for availability.
To help control the 2nd clutch apply pressure and shift feel in the 4T65-E, a 1-2 accumulator piston and accumulator valve regulating fluid pressure are used. The 1-2 accumulator valve regulates line pressure using torque signal influence and directs 1-2 accumulator pressure to the spring side of the piston, controlling the 2nd clutch apply. Wear at the bore or valve can allow torque signal, 1-2 accumulator or line pressures to exhaust, resulting in various 1-2 shift complaints. The oversized Sonnax valve is made from wear-resistant, hard-coat anodized aluminum to prevent future wear in a refurbished bore. Annular grooves have been added to the valve spool to hydraulically center the valve in the bore for wear resistance.
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.
March 21, 2013
Topics: Vacuum Testing Vacuum Test Guides Transmission GM 4T65-E TransmissionRead Now
Contact a Sonnax Parts Distributor.
Vacuum testing at the port(s) indicated fails to hold the recommended minimum in-Hg, or if wear is visually detected.