Description
4R44E / 4R55E / 5R44E / 5R55E Boost Valve Kit, Sonnax 37947-01K.
Some typical problems in Ford 4R44E, 4R55E, 5R44E and 5R55E units are soft shifts, delayed Reverse, poor modulator control and/or low line pressure in Reverse. A worn boost valve is often the cause, allowing Reverse and/or TV pressure to cross leak or exhaust. Sonnax offers two replacement boost valve kits for these units: the OE ratio boost valve kit 37947-01K and the increased ratio boost valve kit 37947-03K. The 37947-01K has OE spool ratios, to return line rise to stock condition. The 37947-03K assembly has increased ratios for slightly higher line pressures.
- Sleeves are manufactured from highly wear-resistant aluminum alloy
- Hardcoat anodized aluminum valve combats premature wear
- Tight tolerances restore the hydraulic integrity of the assembly
- Kits improve engagement related to loss of boost oil and increased line rise in forward and reverse
- Drop-in Zip Valve™ parts install quickly and easily
OE sleeves may come in either a 3- or 2-circuit design. Boost valve kits 37947-01K and 37947-03K may be used to replace either version.
- Valve
- Sleeve
Symptoms:
- Delayed Reverse
- Soft shifts
- Low line pressure
- Poor modulator control
Cause:
A worn boost valve or boost valve sleeve.
Correction:
Restore proper line pressure control and prevent future wear Sonnax drop-in boost valve kits.
