Sonnax 4R44E 4R55E 5R44E 5R55E Zip Kit Valve Body Kit

This is the Sonnax Zip Kit, part number 4R44E-5R55E-ZIP, for the Ford four- and five-speed Ranger and Explorer family valve bodies: 4R44E, 4R55E, 5R44E and 5R55E. These units wear their valve bores long before anything else fails, and the pressure that leaks past those worn bores is what a rebuilt unit comes back on. This kit is the fix for the bore wear, not a band-aid on the symptom.

The kit reseals the circuits that actually cause the complaints: main line, EPC, solenoid feed and converter charge. Loss in those circuits is what shows up on the bench as low or erratic line pressure, slipping and delayed engagement, a shudder or lockup code from the converter circuit, and solenoid performance codes that read like an electrical fault when the real problem is hydraulic. Sealing the bore ends up fixing several trouble codes at once.

Every Zip Valve part in the kit is drop-in. There is no reaming, no oversized bore work and no special tooling, so you can do the repair with the valve body on the bench during a normal overhaul instead of sending the casting out or sourcing a replacement. Pull the valve body, clean it, install the kit parts in the affected bores, and reassemble.

Sonnax includes a printed technical booklet with the kit that walks through the installation bore by bore and adds inspection notes for the rest of the valve body, so you can check the remaining circuits while you have it apart. If you are rebuilding one of these units, plan on the Zip Kit going in with it.