5R55 AT Transmission Parts

Specifications

Transmission type

Fully automatic rear-wheel-drive transmission, five forward speeds with 5th gear as overdrive

Mechanical content

3 multiplate clutch packs (coast, direct — single-sided — and forward), 2 one-way clutches (overdrive sprag and low sprag), 3 brake bands (overdrive, intermediate and low/reverse) and 3 compound planetary gear sets (overdrive, forward and rear)

Code meaning

5 = five forward speeds · R = rear-wheel drive · 55 = relative torque capacity · S = synchronous shift transmission · W = wide ratio transmission (ATSG transmission identification)

Variant differences

The 5R55N uses an intermediate clutch and an intermediate sprag; the synchronous 5R55W and 5R55S do not. Internally the W has a 24-tooth overdrive sun gear and the S a 38-tooth overdrive sun gear (Sonnax)

External identification

The 5R55N has two cast bosses behind the intermediate servo cover, the one closest tapped for the PCC pressure port; the W/S has only one boss for the PCC port. With the pan removed, the N also has a base plate similar to the 4R70W over the lower valve body plus a reverse pressure switch, which the W/S does not have (Sonnax)

Control

The shift pattern is controlled electronically with four on/off solenoids taking a ground signal from the PCM; line pressure and shift feel are set by three pressure control solenoids (PCA, PCB and PCC — Ford calls them Variable Force Solenoids) together with a TCC solenoid. All solenoids sit in the solenoid body on the valve body and are not serviced separately (ATSG)

Solenoid body interchange

The solenoid assembly appears to interchange between the N, W and S, but the base plate and the filter do not: mixing them makes the unit lose reverse, TCC apply and solenoid oil pressure (Sonnax)

Fluid caution

The fluid problem in the 5R55E, W, S and N was caused by a factory ATF fill of early Mercon V before May 2005. Ford released an interim additive package, 4L2Z-19B546-AB with fluid XL-11, under bulletin FSA 04B22; the final resolution was revised Mercon V, XT-5-QM in a black quart container (Sonnax)

Servo pin bore wear

Ford TSB 09-12-12 covers loss of 2nd, 3rd and 5th gear with incorrect ratio DTCs caused by servo pin case bore wear reducing apply pressure. The repair is to ream and sleeve the case using the Rotunda 5RW master kit, with cutting oil — substitutes, particularly ATF, may oversize the bore.

Level setting

The N, W and S have no dipstick. The level must be set with the transmission between 80°F and 120°F; if it is set while hot, it will be low once the unit cools, which can cause failure (ATRA technical bulletin)

Common applications

• Ford Explorer and Mercury Mountaineer — 5R55W for 2002–2003, then 5R55S (Sonnax); Ford TSB 09-12-12 covers 2002–2009 Explorer and Mountaineer
• Ford Explorer Sport Trac — 2007–2009 (Ford TSB 09-12-12)
• Lincoln LS and Ford Thunderbird — 5R55N from 1999 to 2002, replaced by the 5R55S in the Lincolns and Thunderbirds in 2003 (Sonnax); TSB 09-12-12 covers Lincoln LS 2002–2006 and Thunderbird 2002–2005
• Ford Mustang — 2005–2009 (Ford TSB 09-12-12)
• Lincoln Aviator — 2003–2005 (Ford TSB 09-12-12)

• Jaguar S-Type 3.0 / 4.0 — 5R55N, 1999 to 2002 (Sonnax)
• Introduced in 2002 in the Ford Explorer and Mercury Mountaineer in both 2WD and 4WD; from model year 2003 also in the Lincoln LS, Lincoln Aviator and Ford Thunderbird (ATSG)

Fitment is listed for reference only — always confirm by transmission code or by sending us two or three photos of the unit before ordering.

What we hold in stock for 5R55

• Friction plate

Click a group to jump to its photos below. The photos show the actual parts we hold.

The photos below are the parts we currently hold for 5R55. If you need a part you do not see, send us the name or two or three photos of the unit — we will photograph the actual stock we have and quote it.