May 21, 2013
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.4R44E, 4R55E, 5R44E, 5R55E
Boost Valve Kit
Part No. 37947-01K
OE Ratio
You need this if... View Instructions Find a DistributorSome 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
Pressure Comparison Between OE and Increased Ratio Boost Valves
| EPC PSI | 37947-01K (OE Ratio) |
37947-03K (Increased Ratio) |
||
|---|---|---|---|---|
| Line | Reverse | Line | Reverse | |
| 30 | 107 | 135 | 114 | 143 |
| 75 | 178 | 224 | 194 | 243 |
| 120 | 250 | 313 | 275 | 343 |
- Valve
- Sleeve
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 4R44E, 5R44E, 4R55E, 5R55E Valve Body Layout
You need this if...
Vacuum testing at the port(s) indicated fails to hold the recommended minimum in-Hg, or if wear is visually detected.
