Symptoms:

1-2 Flare
2-3 Flare
2-1 Clunk
Harsh Reverse
Clutch failure
Band failure
Non-adjustable (high) throttle pressure

Cause:

The boost valve wears the inside diameter of the boost sleeve, allowing TV/EPC and Reverse oil leakage.

Correction:

Sonnax drop-in boost valve kits provide wear-resistant materials, minimum clearance for restored pressure control, and optional O-rings for positive sealing within the bore.

4F50N, AX4N, AX4S, AXOD, AXODE

Boost Valve Kit
Part No. 96201-01K

Fits all except 3.0 liter 12 valve, O-ring style.

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Vehicles with Ford AXOD, AXODE, AX4S or AX4N transmissions frequently have flare 1-2 and 2-3 upshifts, high pressure, harsh Reverse (300 psi), 2-1 downshift clunk, non-adjustable throttle pressure and clutch or band failure from poor line rise. This is caused by wear on the inside bore of the boost sleeve allowing TV/EPC and/or Reverse oil to either leak to exhaust or cross-leak. Sonnax offers boost valve kits for both 3.0 and 3.8 liter applications and sleeves with or without O-rings (factory style) to eliminate the above problems.

Sleeves are made from high-quality aluminum to prevent wear
Hardcoat anodized aluminum valve combats premature wear
O-ring sleeves prevent leakage between the sleeve and valve body bore
Available in two sizes: 96201-12K (O-ring style) with a small diameter boost valve of .475"; 96201-01K (O-ring style) and 96201-08K (factory style) with a small diameter boost valve of .491"
Drop-in Zip Valve™ parts install quickly and easily

Learn More About Zip Valve™ Drop-In Repairs

Contents

Sleeve
Valve .491"
O-Rings (2)

Valve Body Layout

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.