Vehicles with Ford AOD transmissions frequently have problems with poor line rise, which results indirect clutch failures and soft shift slides. These complaints are often caused by severe wear of the boost sleeve, allowing oil leakage. The hardened steel boost valve continuously reciprocates within the aluminum boost sleeve, and wears the inside diameter of the sleeve. This excessive leakage can be eliminated by installing the Sonnax boost valve kit 76990-03K.
|Boost Valve Ratios|
|Part Numbers||Ratios||Great for these Applications|
|76990K & 76990-03K||.545" Spool Standard Ratio||Standard OE|
|76990-04K||.553" Spool Large Ratio||Large Ratio OE & High Performance|
Vacuum testing at the port(s) indicated fails to hold the recommended minimum in-Hg, or if wear is visually detected.