4R70W Overhaul Kit 2003-2014, new and ready to install. Fits the 4R70W. Ships fast from the USA.
This overhaul kit, reference KP37900H, covers the Ford 4R70W from 2003 through the later 4R70E and 4R75E-era units the kit maker lists to 2014. It is the seal and gasket set a builder reaches for when a Crown Victoria, Grand Marquis, Town Car, F-150 or Mustang four-speed is coming apart for a rebuild: the pan is full of dark fluid, the front pump is weeping, or the unit slips once it gets hot. What makes this range tricky is that it straddles the 2004 redesign, so this page spends most of its time on how to tell which side of that line your transmission sits on.
The 4R70W applies its forward, direct, reverse, intermediate and coast clutches and its overdrive band with fluid pressure, and every one of those circuits depends on soft parts: molded piston seals, lip seals, sealing rings on the stator support and drum hubs, O-rings on the servos and accumulators, and the pan and case gaskets. Heat cycles harden the rubber and wear the rings, and the pressure that should clamp a clutch pack leaks to the sump. An overhaul kit renews that material in one teardown so each circuit holds pressure again once the unit is assembled and air-checked.
Scan for codes, check the fluid level hot, and drop the pan. Lining flakes and a heavy gray paste on the magnet mean clutches are burned and the kit is only part of the job. Run a line pressure test as well: Transmission Digest documents pressure regulator bore wear that bleeds EPC pressure back to the pump inlet, and no amount of new rubber fixes that. Our 4R70W Crown Victoria common problems guide lays out the checks in order, and the F-150 shift problems guide covers the truck side.
The listing covers 2003-2014. ATRA's interchange notes show why that span needs care. The 2004-up 4R70E and 4R75E pump uses a larger bonded rubber intermediate piston, while the earlier 4R70W pump uses an aluminum piston, and the two cannot be swapped piece for piece. The stator support on the later unit carries thin plastic forward sealing rings where the 4R70W used cast iron rings. A 2003 transmission and a 2005 transmission therefore do not take every seal in the same position, so lay the kit out against your old parts before assembly. Match your case connector (black on 1998-up units) and the tag on the case, or send us your year and VIN and we will confirm it. You can browse every part for this family on the 4R70W collection page.
If your unit is a 2004 or later only, the lower-cost 4R70W overhaul kit for 2004-2014 is also worth comparing.
| Fits | 4R70W 2003-2014 |
| Part type | Overhaul Kit |
| Condition | New |
| Brand | OEM |
| Reference | KP37900H |
| 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 2003-2014, but the pump intermediate piston and stator support sealing rings changed with the 2004 4R70E/4R75E. Compare the kit to your old seals during teardown, and send us your year and VIN if you want fitment confirmed before ordering.
It is the reference number carried on this kit. Use it to compare against the kit your rebuilder or parts book calls for.
An overhaul kit is the seal and gasket set. Check the product photos for what is in the box; if your frictions are burned, plan on a friction and steel set as well.
Use what your owner guide specifies. Ford lists MERCON V for the 2003 Crown Victoria, and the 2009-up Panther cars changed to MERCON LV.
Only if the pressure loss was at the seals. A worn pressure regulator valve bore in the valve body causes the same symptom, so run a line pressure test before and after.
