5R55S Valve Body Replacement: Step-by-Step Guide

5R55S Valve Body Replacement: Step-by-Step Guide

5R55S Valve Body Replacement: Step-by-Step Guide

Your Mustang, Thunderbird or Lincoln with the 5R55S is flaring, slow into reverse, or setting transmission codes, and the valve body is the suspect. It comes out from underneath with the transmission in the car, but early and late valve bodies differ, the fill is easy to get wrong, and the relearn has to be done right. This guide covers diagnosis, removal, torque, fill and fast learn.

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Not sure the valve body is really the problem yet? Read 5R55S valve body symptoms and how to know yours is failing first.

Confirm You Have a 5R55S

The 5R55S shares a lot with the 5R55W and 5R55N, and a Texas transmission shop's rundown of Ford's 5R55 versions notes that only a few parts interchange between the 5R55N and the W or S models. That same source says the 5R55S went into the 2005-and-later Ford Mustang, and that in 2003 the Thunderbird and Lincolns switched to the 5R55S with SelectShift, which lets the driver shift manually without a clutch. If you are unsure which version is under your car, check with our 5R55S vs 5R55W vs 5R55N identification guide before you buy anything.

Diagnosis Steps Before You Drop the Pan

  1. Scan every module and fix the codes. A 5R55W/S/N installation guide says you must scan the vehicle and fix all codes, and warns that if any codes are present in any module, the PCM will not relearn.
  2. Suspect the solenoid pack too. Sonnax's valve body listing carries a tech warning that a defective solenoid pack can produce multiple fault codes, and Sonnax recommends replacing the pack whenever a transmission problem or failure occurs. Our 5R55S/5R55W solenoid pack failure guide covers how to tell the two apart.
  3. Consider servo pin bore wear, especially with a delayed reverse. Sonnax explains that as the case servo pin bore wears, apply oil leaks into the barrel area of the case, which hurts shift timing and band apply pressure, and release oil cross-leaks into the apply circuits. In reverse both servos are charged from the release side, so pin bore wear causes delayed reverse. A new valve body does not fix a worn case. See 5R55S servo bore wear and the real fix.
  4. Look for foamy fluid. Sonnax states the 5R55N, 5R55W and 5R55S are prone to foaming fluid in the sump from excess exhaust and valve body wear, which leads to fluid coming out the vent and incorrect fill readings.

Match the Replacement to Your Casting

This is the step that decides whether the job works. Sonnax splits the 5R55S/W valve body into two parts: F032 for '01-'08 and F035 for '09-later. According to Sonnax, in 2009 Ford changed the casting, the rough forging number location and the worm tracks, and reduced the hole sizes in the VFS1 and VFS2 oil circuits of the separator plate. Sonnax lists these rough forging numbers:

  • '01-'08: RF1L2P 7A101GA or RF5L2P 7A101CA
  • '09-later: RF9L2P 7A101AA

Read the number off your old valve body and compare it to the replacement before anything gets bolted up.

Tools and Parts

  • Inch-pound torque wrench
  • Cut-down 10mm ratcheting combination wrench for the solenoid block connector, a tip from an experienced owner on Explorer Forum
  • Replacement valve body matched to your casting
  • Solenoid pack, new filter and pan gasket
  • Mercon V, which the 5R55W/S/N installation guide lists as required
  • Fluid pump and a scan tool that shows transmission temperature

Removing the Old Valve Body

  1. Drain and drop the pan. Explorer Forum owners count roughly 16 pan bolts on this family.
  2. Remove the filter. Roughly 4 fasteners, per the same thread.
  3. Disconnect and remove the solenoid block. About 8 Torx bolts hold the block, and the connector on top is tight.
  4. Disconnect the shift linkage. The thread notes it has to come off too.
  5. Remove the valve body bolts and keep them in order. Owners report about 20 bolts. Push each into a cardboard outline of the valve body as it comes out so every bolt goes back in its own hole.
  6. Lower the valve body straight down and set it beside the replacement.
  7. Keep the manual valve. Sonnax's F035 instructions say the solenoid pack is not included and to save your existing manual valve for reuse with the remanufactured valve body.

Installing the Replacement

5R55S shift solenoid block pack with filter and pan gasket
5R55S Shift Solenoid Block Pack with Filter: solenoid pack, filter and pan gasket for the same pan drop.
  1. Clean the case mating surface so nothing holds the valve body off the case.
  2. Transfer the manual valve if required, then raise the valve body into place, engaging the manual valve with the linkage.
  3. Start every bolt by hand in its original hole.
  4. Torque to 89 in-lb in sequence. Sonnax gives a valve body-to-case torque of 89 in-lb using the proper sequence, and its F035 instruction sheet includes the sequence diagram.
  5. Reinstall the solenoid block and connector. The installation checklist calls for inspecting the wiring harness and connector for damage or corrosion.
  6. Install the new filter and pan gasket, then the pan.
  7. Reconnect the shift linkage and check adjustment. The installation guide calls range sensor and shifter cable adjustment very critical on this transmission. With the cable disconnected, confirm park by trying to turn the wheels, move the linkage two detents away from park to find neutral, and confirm the cable end lines up with the manual lever.

Filling the 5R55S

The installation guide calls the 5R55 an unusually difficult transmission to fill and warns that a bad fill causes shifting and performance problems. Its procedure:

  1. Remove the T30 plug from the stand pipe. Engine off, pump fluid into the small opening in the pan until it runs out the stand pipe in a steady stream, then install the plug hand tight.
  2. Start the engine, pull the plug and keep filling until a steady stream develops again.
  3. Final check: transmission at 80 to 120 degrees on the scan tool, engine running, in park or neutral. Remove the plug; you should get a steady stream. Let it drain until the stream fluctuates and air bubbles appear, then reinstall the plug before the flow stops. Letting it stop completely leaves it underfilled.

Fast Learn

The same guide says to run a fast learn after major transmission repair or solenoid block replacement. Fix all codes, have at least 1/3 tank of fuel and at least 12.2 volts at the battery with the key off, then disconnect the battery for at least 15 minutes. Bring the transmission to 170 degrees F and the engine to operating temperature. With the engine running, shift park to reverse 5 times, reverse to drive 5 times and neutral to drive 5 times, holding each gear 5 seconds. Shut off the engine, remove the key and open the driver's door so the modules sleep and keep the relearn. The guide says proper shift patterns can take another 200 miles, and to drive easy for the first 300 miles: no towing and no more than half throttle.

Replace While You Are In There

  • Solenoid pack. It is not included with the Sonnax reman valve body, and Sonnax recommends replacing it whenever there is a transmission problem.
  • Filter and pan gasket. Our 5R55S transmission filter 2002-2010 (OEM 3W4Z7A098AA) fits this job.
  • Servo parts, if delayed reverse was a complaint. Sonnax's 56361J-01K sleeve kit repairs the overdrive and intermediate servo pin bores on the 5R55N, 5R55W and 5R55S with the S-56361J-TL tool kit. That is case machining and a bench job. A 5R55S servo piston kit belongs in the same repair.

Everything else for this unit is in our 5R55S transmission parts collection.

Cost and Effort

This is a moderate in-car job, not a transmission removal. Expect most of a day for a first-timer between the tight solenoid connector, the bolt count, the fill and the fast learn; the Explorer Forum owner called it messy and tedious by hand. The expensive mistake is buying a valve body when the fault was the solenoid pack or servo bore wear, or installing an '01-'08 unit on an '09-later transmission.

Frequently Asked Questions

What is the 5R55S valve body bolt torque?

Sonnax specifies 89 in-lb for the valve body-to-case bolts, tightened in sequence. Use an inch-pound torque wrench.

Are 2008 and 2009 5R55S valve bodies interchangeable?

Do not assume so. Sonnax sells separate '01-'08 (F032) and '09-later (F035) units because Ford changed the casting, worm tracks and VFS1/VFS2 separator plate hole sizes in 2009. Match the rough forging number on your old valve body.

Do I need a relearn after replacing the valve body?

Yes. The 5R55W/S/N installation guide says a fast learn should be performed after major transmission repair and after solenoid block replacement, and the PCM will not relearn if any codes remain in any module.

Sources