4R55E Solenoid Kit, remanufactured and ready to install. Fits the 4R55E. Ships fast from the USA.
If your mid-1990s 4.0L Ford or Mazda truck with the four-speed 4R55E is banging into gear, flaring on the 1-2 or 2-3, refusing to lock the converter, or throwing a converter slip code, this is the complete electrical side of the valve body in one box. The set pictured is six remanufactured solenoids: four square-body shift solenoids and the two cylindrical units with the mounting tabs that run electronic pressure control (EPC) and converter clutch (TCC). Replacing all six at once takes the solenoids off the suspect list for good, which matters on a transmission where the hydraulics behind them are just as likely to be the problem.
The 4R55E is the beefed-up 4.0L version of the 4R44E. Sonnax dates its release to 1996, and for 1997 Ford reworked the same case into the five-speed 5R55E by using the front servo for an overdriven first. The four on-off shift solenoids (SSA, SSB, SSC and SSD, which also handles the coast clutch) set the position of the shift valves. The EPC solenoid controls line rise: as its output climbs, an engagement control valve opens to line pressure and boosts it further. The TCC solenoid ramps its duty cycle to stroke the TCC modulator valve, which switches converter feed from the pressure regulator to the TCC regulator. Because that regulator is itself fed by line pressure, a weak EPC solenoid can show up as converter slip, not just soft shifts.
Be honest with yourself about the hydraulics. Sonnax notes that true shift solenoid failures are rare on this family; loss of solenoid oil from loose valve body end plugs is far more common, and the EPC and TCC bores wear with use. Ohm each solenoid at the case connector (our multimeter solenoid test guide walks through it), then put a gauge on the case. Good maximum EPC is roughly 125-130 psi in overdrive and up to 144 psi in reverse, and it should not drop more than 15 psi when the converter applies. If pressure is low with a good EPC solenoid, see our line pressure checking guide and plan on valve body work as well.
This is the general 4R55E listing, without a year range in the title. The 4R44E, 4R55E, 5R44E and 5R55E share a solenoid layout, but Ford changed valve bodies, separator plates and solenoids several times after 1995, so compare connector style, mounting tabs and the part numbers stamped on your originals before ordering. If you would rather we check it, send your year and VIN. Owners of an early truck can also compare this set against our year-specific 1995 4R55E solenoid kit.
If the EPC circuit fails an air test, a Sonnax 4R44E/5R55E Zip Kit addresses the worn bores, or you can step up to a remanufactured 4R55E valve body that arrives with the circuits already corrected. Either way, a new pan gasket and filter from an overhaul kit is cheap insurance while the pan is off.
| Fits | 4R55E |
| Part type | Solenoid Kit |
| Condition | Remanufactured |
| Brand | OEM |
| Ships | From the USA |
| Warranty | 1-year |
The set pictured is six remanufactured solenoids: four square-body on-off shift solenoids and the two cylindrical tabbed units for EPC (line pressure) and TCC (converter clutch). That covers every solenoid on the 4R55E valve body.
The 4R55E was the 4.0L version of the 4R44E in mid-1990s Ford and Mazda rear-drive trucks, replaced by the five-speed 5R55E for 1997. Solenoids changed across revisions, so match connector style, tabs and stamped numbers on your originals, or send us your year and VIN to check.
Not always. Shift solenoid failures are uncommon on this family; EPC and TCC solenoids wear far more. Many owners replace the set anyway because the pan is already down, but test them first and check line pressure so you do not miss a valve body leak.
The EPC circuit leaks at several points in the valve body and the EPC and TCC regulator bores wear. A new solenoid cannot make up for that leakage, so low line pressure with good solenoids means valve body repair.
Use MERCON-family ATF; Ford's current service fluid for these transmissions is MERCON V. Clear codes after installing and drive through a full warm-up so the PCM can relearn shift pressure.
