- 2nd Gear starts
- Delayed Forward
- Erratic shifts
- Gear ratio & solenoid codes
- Low line rise
- No 3rd when hot
- No 4th when hot
- Soft shifts
- TCC apply concerns
Loss of oil pressure due to worn components in critical oil circuits.
Zip Kit seals critical pressure losses
- Boost Valve & Sleeve Kit
- Forward Modulator Valve, PTFE Seal, End Plug, Spring, & O-Ring Large O-Ring
- Reverse Modulator End Plug & O-Rings 2 Medium O-Rings
- 2-3/3-4 Shift Valve End Plug & O-Rings 2 Small O-Rings
- 1-2/2-3 Shift Valve End Plug & O-Rings 2 Medium O-Rings
- Converter Regulator Valve End Plug, Spring, & O-Rings 2 Large O-Rings
- Kick Downshift, Manual Low & Throttle Downshift End Plugs (2) 1 Large, 1 Small
- Kick Downshift, Manual Low & Throttle Downshift O-Rings (6) 2 Large, 4 Small
- Extra End Plug O-Rings (6) 2 Large, 2 Medium, 2 Small
- Checkballs (4) Plastic
- EPC Limit Valve
- Lube Orifice Plug
- “L” Pins (2)
- TCC Apply & OD Servo Apply Pressure Modification Drill Bits (4) .055” dia., .062” dia., .072” dia. & .110” dia.
- Plug Aluminum, .062”
- Shift Solenoid O-Rings (8) 4 Small, 4 Large
Sonnax Zip Kit 4R44E-5R55E-ZIP targets the root cause of multiple complaints by sealing the critical circuit pressure losses in the Ford 4R44E, 4R55E, 5R44E and 5R55E valve bodies. The kit contains uniquely designed parts to prevent the loss of pressures within the main line, EPC, solenoid feed and converter circuits. This kit also includes modifications that provide firmer shifts, improves intermediate servo and direct clutch pressure, and improves TCC apply. The kit also seals multiple circuits known to suffer from end plug leakage or poor checkball sealing. No special tools are required for installing these parts.
The Zip Kit quick guide provides clear and easy instructions on one sheet to get the unit sealed up and back on the road fast. In addition to general rebuilding tips and technical information, the technical booklet included in this kit contains vacuum testing and additional repair options for higher mileage units or for repairing specific complaints which are beyond the scope of this kit.
- No Reaming required
- Installs quickly with no special tools required
- Uniquely designed parts address root cause of valve body complaints by sealing critical pressure circuits
- Detailed technical booklet included with in-depth rebuild and inspection tips for comprehensive valve body repair
In addition to general rebuilding tips and technical information, the technical booklet included in this kit contains vacuum testing and additional repair options for higher mileage units, or for repairing specific complaints which are beyond the scope of this kit.
Click on the unit names to view all recommended Sonnax repair options for these transmissions.
The Sonnax ZIP KIT®
The First Step in Correcting Common Shift Problems
It's easy to restore and extend vehicle shift quality with Zip Kits. Uniquely designed Sonnax parts target the root cause of valve body complaints and stop critical circuit pressure losses in the most common problem areas of the transmission.
Click here to view PDF if instructions do not appear below.
Valve Body Layouts
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