Five-piece solenoid set with EPC, TCC and three shift solenoids for Ford AX4S, AX4N and 4F50N front-drive 4-speeds that slip, flare or stick in gear.
A Ford Taurus or Mercury Sable, a Windstar or Freestar van, or a Lincoln Continental with the front-drive four-speed that slides into second, bangs into gear, never locks the converter, or suddenly holds one gear with the overdrive light flashing often has an electrical control fault behind it. This five-piece kit replaces the full solenoid group on the AX4S, AX4N and 4F50N: the electronic pressure control (EPC) solenoid, the torque converter clutch (TCC) solenoid, and the three on/off shift solenoids. The two bracket-mounted cylindrical units in the photo are the EPC and TCC solenoids; the three square-bodied units are the shift solenoids.
On these transaxles the valve body sits behind the side cover rather than in the bottom pan, and TransGo's AX4N layout labels the solenoids mounted on it as SS1, SS2, SS3, EPC and the PWM converter clutch solenoid. The powertrain computer turns the three shift solenoids on and off in combinations that move the 1-2, 2-3 and 3-4 shift valves. The EPC solenoid is a variable pressure control: the computer adjusts its current to set line pressure, and with it how hard each clutch and band applies. The PWM solenoid cycles converter clutch apply so lockup feels smooth. Because EPC sets pressure for everything, a weak EPC solenoid shows up as slipping or harsh shifts in every gear, not just one.
Scan for codes, then measure each solenoid's resistance at the case connector and compare with your service information; our guide on testing a transmission solenoid with a multimeter covers the method. Pressure complaints deserve a gauge reading before parts go in, because a sticking main regulator or a valve installed incorrectly can mimic a bad EPC solenoid; see our line pressure testing guide. Intermediate clutch failures are common across the AX family, so a long 1-2 shift with normal electrical readings may be a worn clutch rather than a solenoid. If shift quality is the main complaint, the AX4N valve body shift kit addresses the hydraulic causes, and this kit covers the electrical side.
The listing covers the Ford transverse four-speed family: AX4S (1993-2003 Taurus and Sable, 1995-2000 Windstar), AX4N (Taurus from 1994, Sable, 1995-2002 Continental, 2001-2003 Windstar) and the 4F50N, the 2001-on name for the AX4N used through the 2004-2007 Freestar and Monterey. The source listing describes 1997 and later model years. Solenoid brackets and connector shapes changed over that long run, so match the bracket and plug on each part you remove before tightening anything, or send us your year and VIN. The transmission data plate code helps: X marks an AX4N or 4F50N and L marks an AX4S.
Drain the fluid, then remove the side cover to reach the valve body. Unplug the internal harness and change the solenoids one at a time so each new part goes in the same spot as the old one. Lube every O-ring with clean fluid, seat the solenoid by hand, and snug the bracket bolts without overtightening into the aluminum. TransGo warns that valve body bolts on this unit work loose and cause comebacks, and calls for re-tightening them to 110 inch-pounds. Refill with MERCON V; a case of Motorcraft MERCON V covers the refill and a follow-up change. Heat kills these transaxles, so check the engine coolant level and radiator condition and consider an auxiliary cooler such as the Hayden 403 tube-and-fin cooler. Read why transmissions overheat for the details, then clear codes and road test through every gear.
| Transmission | Ford AX4S, AX4N, 4F50N |
| Pieces | 5 |
| Includes | EPC solenoid, TCC solenoid, 3 shift solenoids |
| Model years | 1997 and later (per source listing) |
The Freestar uses the 4F50N, which is the renamed AX4N, and this kit is listed for AX4S, AX4N and 4F50N units. Match the bracket and connector of each removed solenoid against the new one, or send your VIN and we will check.
Five solenoids: the EPC solenoid, the TCC solenoid, and three on/off shift solenoids, matching the photo.
No. They mount on the valve body behind the side cover, which is serviced with the transaxle in the vehicle. Have a new side cover gasket and fresh fluid on hand.
MERCON V. TransGo also recommends a synthetic-blend MERCON V for durability and stresses keeping the engine cooling system healthy, because the transaxle depends on the radiator cooler.
Only if the electrical checks or line pressure point to them. A worn intermediate clutch is a common AX-family failure and produces the same long 1-2 shift, so test resistance and pressure first.
