Replaces the shift, EPC and TCC solenoids and internal harness on 2005-2008 Ford 4R70W and 4R75W in the F150, E-Series and Town Car.
When a 2005-2008 F-150, E-Series van, Town Car or Grand Marquis starts in a tall gear, will not shift into overdrive, slides through shifts or stops locking the converter, the fault is very often somewhere in the transmission's electrical package rather than in the clutches. This kit replaces that whole package on the late 4R70W and 4R75W in one go: the dual shift solenoid pack, the EPC (electronic pressure control) solenoid, the TCC solenoid and the rigid internal harness that carries power and ground from the case connector to each of them. The listing photo shows all four pieces, and the maker part number is SNTS4R70W.
The 4R70W chooses its four forward gears with just two on/off solenoids, SS1 (A) and SS2 (B), mounted together in the silver dual pack. SS1 alone gives 1st, both off gives 2nd, SS2 alone gives 3rd and both on gives 4th. The brown EPC solenoid is a variable force unit that sets line pressure, and the TCC solenoid applies the converter clutch at cruise. None of them work without the internal harness. On this design it is a molded plastic lead frame clipped along the valve body, and both shift solenoids share a single 12-volt feed through it. A cracked frame or a loose terminal can make good solenoids look dead, which is why replacing the harness along with the solenoids makes sense on a high-mileage truck.
Write down which gear the vehicle is stuck in, then check each circuit at the case connector before you drop the pan. Per the Sonnax Zip Kit booklet the shift solenoids read about 20-30 ohms, the TCC about 10-16 ohms and the EPC only 2-5 ohms, so a low EPC reading is normal. If every shift circuit reads open from the common feed pin, you are looking at the harness or connector, not four failed solenoids. Use a meter, never a test light. Our 4R70W shift solenoid testing guide has the full gear-to-fault chart and connector pinouts, and the EPC solenoid guide explains why a slipping truck may need valve body work rather than a new EPC.
Listed for 2005-2008 Ford F-150, E-150, E-250 and E-350, Lincoln Town Car and Mercury Grand Marquis with the 4R70W or 4R75W. Sonnax groups the 1998-2008 units into one case connector generation and treats 2009-up as a different design, so a 2009 truck needs a different harness. Harness routing and solenoid mounting can still vary within a year range, so lay your old harness next to the listing photos and compare the connector and lead frame shape, or send us your year, model and VIN and we will check it. Everything else we carry for this unit is in the 4R70W parts collection.
Drain and drop the pan, pull the filter, then unclip the old harness from each solenoid and from the case connector. Swap one component at a time so nothing ends up in the wrong bore, lube every O-ring with fluid and check none are rolled or pinched, and seat each terminal until it clicks. Transmission Digest documented a rebuilt 4R70W that took off in a higher gear with fresh solenoid codes because two connector terminals had pushed back into a poor-quality aftermarket connector, so tug-test every pin before the pan goes back on. Torque the retaining bolts evenly, refill with Mercon V only, clear codes and reset adaptive memory. A filter is not part of this kit; if you want one in the same box, the 2005-2008 solenoid kit with filter includes it, and a deep aluminum 4R70W pan with drain plug makes the next service a lot cleaner.
| Type | Shift, EPC and TCC solenoid kit with internal wire harness |
| Fits | Ford 4R70W, 4R75W (2005-2008) |
| Vehicles | 2005-2008 Ford F150, E150, E250, E350; Lincoln Town Car; Mercury Grand Marquis |
| Maker part number | SNTS4R70W |
| Weight | 1.5 lb |
Doing this repair right usually means replacing these at the same time. Same transmission, ships together.
No. Sonnax lists 2009-up 4R70W and 4R75W units as a separate case connector generation, so the harness in this 2005-2008 kit is not the right part. Send us your VIN and we will point you to the correct harness.
Both shift solenoids share one power feed through the harness, and the plastic lead frame gets brittle after years of heat. A cracked frame or loose terminal sets solenoid codes that come back after a solenoid swap, so doing the harness while the pan is down removes that variable.
It fixes shudder caused by a sticking TCC solenoid or a bad TCC circuit. If the converter clutch lining itself is worn or the fluid is burnt, a new solenoid will not cure it, so check fluid condition and codes first.
Mercon V. Ford's fluid chart lists Mercon V for the 4R70W and 4R75W and warns against adding friction modifiers or treatments.
Clear the codes and reset the keep-alive memory so the PCM drops the shift adaptations it learned around the failing parts, then drive it gently through every gear for the first few trips while it relearns.
