4R70W Master Rebuild Kit 2004

This master rebuild kit is listed for the 2004 Ford 4R70W, the year the transmission picked up a turbine speed sensor and a new output speed sensor arrangement. If your 2004 Mustang, Heritage-body F-150, Crown Victoria, Grand Marquis or Town Car is slipping in gear, the fluid smells burned, there is clutch material on the pan magnet, or it leaks from more than one seal, a complete soft-parts overhaul is usually cheaper in the long run than patching one circuit at a time.

What a master rebuild kit does in a 2004 4R70W

The 4R70W is a four-speed rear-drive overdrive automatic built on a Ravigneaux gear set. Its clutch packs and bands (forward, direct, reverse, intermediate and coast clutches plus the overdrive and reverse bands) do all the work of changing gears, and every one of them is sealed by rubber and Teflon rings that harden with heat and age. A master kit renews the friction material and the sealing in one job, so the unit goes back together with consistent apply pressure in every circuit instead of one new pack sitting next to four tired ones.

What makes 2004 different is the electronics around those clutches. Per ATRA's interchange notes, the 2004-up output speed sensor reads 24 extended park pawl lugs instead of six holes in the ring gear, and the parts do not interchange with earlier units. The turbine speed sensor added for 2004 reads the forward drum through the sun gear shell, which is why that shell must be the non-magnetic 2004-up version. Get either wrong during the rebuild and the truck comes back with harsh or missing shifts and ratio or speed sensor codes, even with fresh clutches.

Symptoms that call for a full rebuild

• Slipping or flaring in one or more gears, worst when the fluid is hot
• Burned fluid and friction material on the magnet when the pan comes down
• Leaks from several places at once, such as the front pump seal, pan and extension housing
• A bind-up feel on the 1-2 or 2-3 shift and a burned direct clutch, the classic 2001-and-later cross leak
• Grinding or a pan full of metal from the rear planetary carrier, a failure Transmission Digest reports clustering on 2004-2008 units

How to confirm it needs a rebuild before you buy

Pull codes and a freeze frame first. A full set of solenoid codes at once usually points to a lost power feed, not a dead transmission, and a TSS or OSS fault can feel exactly like slipping. Check the fluid hot at the dipstick, then drop the pan: fine gray paste is normal wear, while black friction flakes and brass or steel chunks mean the unit needs to come apart. Our 4R70W F-150 common problems guide walks the order we check things, and the Expedition shift problems guide covers the hydraulic causes that burn clutches on heavy, loaded trucks.

Fitment

This listing is for 2004 4R70W transmissions. 2004 is a split year: the redesigned 2004 F-150 and some Expeditions and Panther cars carry a 4R75-series unit instead, depending on engine and build date, and those take a different kit. Read the transmission code on the door tag and the ID tag on the case, count the frictions in your old packs against the kit, or send us your year and VIN and we will confirm before it ships. If your tag says 4R75W, the 4R75W master rebuild kit for 2004 is the matching part, and every other version is on the 4R70W collection page.

Install notes

• Soak the new frictions in MERCON V before assembly and air-check every clutch circuit before the unit goes back in the case.
• Set each clutch pack clearance with selective snap rings or plates; do not assume the stock stack is right after new frictions.
• Inspect the pump, drum and planetary carrier bushings while the unit is open, and look hard at the carrier's captured needle bearing on a 2004.
• Reuse only a non-magnetic 2004-up sun shell, and keep the 2004 speed sensors and ring gear together.
• On this post-2001 valve body, fix the cross leak under the 2-3 accumulator and consider a calibrated 4R70W shift kit while the valve body is off.
• Tired solenoids undo a rebuild. The 1998-2004 shift solenoid and filter kit covers this year.
• Prime the pump, fill with MERCON V, and set the final level hot at the dipstick after a road test.

Will this kit fit a 2004 F-150?

Only if the truck has a 4R70W. The 2004 Heritage F-150 kept the 4R70W, but the redesigned 2004 F-150 moved to a 4R75-series unit. Check the transmission code on the door tag or send us the VIN and we will confirm.

Can I use a pre-2004 sun shell or output sensor with this rebuild?

No. ATRA's interchange notes say the 2004-up output speed sensor and ring gear do not interchange with earlier parts, and the 2004-up sun shell must be non-magnetic so the turbine speed sensor can read the forward drum. The wrong shell causes harsh or no shifts with ratio and speed sensor codes.

What fluid does a rebuilt 2004 4R70W take?

MERCON V. Ford's Motorcraft data recommends MERCON V where MERCON V or MERCON is specified and warns against using it where MERCON LV, ULV, SP or Type F is called for. Soak the frictions in it before assembly and set the level hot.

What else should I replace with a master rebuild kit?

Bushings, any worn drums or planetary parts you find on teardown, and tired solenoids. On a 2004 also inspect the rear planetary carrier and its captured needle bearing, and address the 2001-up cross leak under the 2-3 accumulator before the valve body goes back on.

My 2004 has several solenoid codes and will barely move. Do I need a rebuild?

Not necessarily. A full set of solenoid codes at the same time usually means the transmission lost its power feed through the harness or connector. Diagnose the wiring before you pull the unit.

• 4R70W F150 Common Problems and Fixes
• 4R70W Expedition Shift Problems: Diagnosis and Fix
• 4R70W Crown Victoria Common Problems and Fixes
• 4R70W F150 Shift Problems: Diagnosis and Fix