Sonnax 37947-01K OE Ratio Boost Valve Kit for Ford 4R44E 4R55E 5R44E 5R55E Transmissions

The Sonnax 37947-01K is an OE ratio boost valve kit designed to restore proper line pressure control in Ford 4R44E, 4R55E, 5R44E, and 5R55E automatic transmissions. This kit features OE spool ratios to return line rise to stock condition.

A worn boost valve is often the cause of common transmission problems including soft shifts, delayed reverse, poor modulator control, and low line pressure in reverse. The worn valve allows reverse and TV pressure to cross leak or exhaust.

Key Features:

• Sleeves manufactured from highly wear-resistant aluminum alloy
• Hardcoat anodized aluminum valve combats premature wear
• Tight tolerances restore the hydraulic integrity of the assembly
• Improves engagement related to loss of boost oil and increased line rise in forward and reverse
• Compatible with both 3-circuit and 2-circuit OE sleeve designs

This drop-in replacement kit provides a cost-effective solution to restore hydraulic integrity and eliminate shift quality issues caused by boost valve wear. For applications requiring slightly higher line pressures, Sonnax also offers the 37947-03K with increased ratios.