• Soft slide shifts
  • Delayed Reverse
  • Low line rise
  • Direct clutch failure


Severe wear of the pressure regulator boost sleeve allows boost oil leakage.


The Sonnax drop-in kit includes a highly wear-resistant aluminum sleeve to restore hydraulic integrity, and incorporates O-rings to provide positive sealing in the casting bore.


Boost Valve Kit
Part No. 76990K

O-Ring Style

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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 pressure regulator 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 excess leakage can be eliminated by installing Sonnax boost valve kit 76990K.

  • Highly wear-resistant aluminum sleeve prevents wear
  • O-Rings on sleeve provide positive seal in the casting bore
  • Steel valve has been tightly toleranced to allow minimum clearance with the inside diameter of the sleeve
  • Sleeve and valve restore the hydraulic integrity of the assembly
  • Drop-in Zip Valve™ parts install quickly and easily
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
Learn More About Zip Valve™ Drop-In Repairs

O-Ring seals are added insurance against boost oil loss. Sleeve can be installed without these seals, but their use is recommended

  • Valve
  • Sleeve
  • O-Rings (3)

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.

Ford AOD Valve Body Layout

Ford AOD Valve Body Layout
  • AOD Boost Valve Kit 76990K
  • AOD Boost Valve Kit 76990K

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AOD Boost Valve Kit Vacuum Test Locations