5R55W Pump 2001, remanufactured and ready to install. Fits the 5R55W. Ships fast from the USA.
If your Explorer or Mountaineer with the 5R55W sits in Drive on a cold morning and will not pull until you blip the throttle, or it groans at idle and feels soft in every gear once the fluid is hot, the front pump belongs on your short list. This listing is a rebuilt complete pump assembly for the 5R55W, sold under Ford service number 5L2P-7B325-AA and listed for 2001-and-later W, S and N units. Each pump is torn down, cleaned and checked, and any bushing or part that is out of spec is replaced before it ships.
The converter hub drives the pump gears, so everything hydraulic in the W - shift solenoid feed, clutch and band apply, converter charge and cooler flow - starts here. Inside the pump body is a line pressure relief and flow control valve that dumps excess oil back to the suction side so the pump does not waste horsepower at highway speed. Sonnax notes that when the canister and plunger wear, the plunger can stick open or leak, and the O-ring that seals it relaxes. When that happens the oil the transmission needs goes straight back to the inlet, and pressure collapses no matter how healthy the valve body is.
ATSG traced the classic cold-morning complaint on the N/W/S to the flow control valve lodging on a ridge worn into its sleeve, or to the very thin sleeve O-ring failing to seal against the pump plate. With a gauge on either pressure tap, a stuck valve reads 40 psi or lower. A reading that low in every range, with normal solenoid readings, is a pump problem rather than a shift problem. Before you pull the transmission, also rule out the W's other common faults, especially servo pin bore wear, which causes slipping that looks similar. Our 5R55W pump failure symptoms guide walks through the gauge tests, and the servo pin bore wear guide covers the other suspect.
This pump is listed for 5R55W, 5R55S and 5R55N transmissions from 2001 forward. In real vehicles, Sonnax places the 5R55W in the 2002-2003 Explorer and Mountaineer, so the 2001 date reflects when production of those trucks began, not a 2001 model year W. Sonnax also warns that the N shares only a few parts with the W and S, so if you have a Lincoln LS, Thunderbird or Jaguar S-Type with the N, confirm your old pump matches before ordering. Compare the casting and bolt pattern with the photo, or send us your year and VIN and we will check it. You can see every other 5R55 part on our 5R55 transmission page.
If the old pump failed from heat or contamination, inspect the valve body and solenoid pack too. A fresh pump feeding a worn regulator bore will still give low pressure.
| Fits | 5R55W 2001 |
| Part type | Pump |
| Condition | Remanufactured |
| Brand | OEM |
| Ships | From the USA |
| Warranty | 1-year |
Doing this repair right usually means replacing these at the same time. Same transmission, ships together.
It is listed for 2001-and-later 5R55W, 5R55S and 5R55N units, and the W and S share their pump design. Compare your old pump with the photo or send your year and VIN and we will confirm before it ships.
It is a complete pump assembly, rebuilt and checked, with worn bushings and out-of-spec parts replaced. You bolt it in as a unit.
That pattern matches the ATSG write-up on the flow control valve sticking in its worn sleeve inside the pump. A pressure gauge reading of 40 psi or lower at the taps confirms it.
Mercon V. Prime the pump with it before the first start, then set the level through the check plug in the pan with the transmission at operating temperature, since the 5R55W has no dipstick.
A front seal, pump gasket and O-ring, and a new filter at minimum. Inspect the converter hub, and check the valve body if the old pump failed from heat or debris.
