Vehicles with GM 4T60 or 4T60-E transmissions often exhibit such problems as poor line rise, soft shifts, poor Reverse boost, and/or 2nd and 3rd clutch distress. These problems can often be caused by worn and leaking boost sleeves. The OE boost valve spools have very narrow contact surfaces within the sleeves, which contribute to the leakage. Sonnax modulated line boost valve kit 84754-17K restores hydraulic integrity.
Vacuum testing at the port(s) indicated fails to hold the recommended minimum in-Hg, or if wear is visually detected.