A 5R55S pan service looks like any other pan drop until you get to the end of it. There's no dipstick and no fill tube, so you can't pour fluid in the top and check it on the stick. Everything goes in and comes out through the bottom of the pan. Done right, it's a one-hour job. Done the way people do a 4R70W, it ends with a unit that's two quarts low and a customer back in a week with a flare on the 2-3.
This guide walks through the Ford procedure for the 5R55W/S in the Explorer and Mountaineer, which is the same unit that went into the 2005-2010 Mustang: the 16 pan bolts, the two filter bolts, the torque converter drain plug most people skip, the reusable pan gasket, the torque specs, and the refill at the level plug. Every number traces to a source listed at the bottom. When something is my own shop habit and not a published spec, I say so.
Before the pan comes down
Confirm it's actually a 5R55S
On a 2006-2010 Explorer or Mountaineer, don't assume. Those trucks came with either the five-speed 5R55S on MERCON V or the six-speed 6R60 on MERCON SP, and they take different fluid. The 2007 Explorer owner guide lists VIN transmission code V for the 5R55S and X for the 6R60. On the 2007 Mustang the 5R55S is code L. The fluid is MERCON V, Motorcraft XT-5-QM in the owner guides. Our 5R55S fluid type and capacity guide covers the fluid side in detail, so this post sticks to the hardware.
What to have on the cart
- A filter and pan gasket kit for the 5R55W/5R55S.
- A new torque converter drain plug. Ford's procedure says a new one must be used to prevent leakage, so don't reuse the old one.
- A 3/16-inch Allen key for the level plug and a wrench to hold the larger drain plug around it.
- The fluid fill tool, Ford 307-437, that threads into the center of the drain plug, plus a suction gun (Ford lists 303-D104) or a fluid transporter to push fluid in from below.
- An inch-pound torque wrench. Most of the fasteners on this job are spec'd in inch-pounds.
- A scan tool that reads the TFT PID. You need fluid temperature to set the level.
- A full case of MERCON V. You won't use all 12 quarts, but once the converter is drained you'll use more than a pan-only service takes, and running out halfway through a level check is how cars go home low.
Step by step: the Ford drain and refill procedure
The sequence below follows the Ford service procedure for the 2002 Explorer and Mountaineer 5R55W/S, as published through Mitchell with Ford's illustrations. The later 5R55S units use the same pan, filter and level-plug design.
- Drain the pan. Raise and support the vehicle, set a drain pan under it and pull the drain plug. That's the large plug in the pan with the small level plug in its center.
- Remove the pan. There are 16 pan bolts. Take them out, drop the pan and set the gasket aside. Don't cut it or throw it away yet (more on that below).
- Remove the filter. It's held by two bolts. Remove them and discard the filter. The filter seals come out with it most of the time. If one stays behind in the bore, get it out before the new filter goes in. Two seals stacked in one bore is a classic suction leak.
- Clean and inspect the pan and magnet. Read the debris before you wipe it off (see "Reading the pan" below).
- Drain the converter. Remove the converter housing access plug, rotate the engine until the converter drain plug lines up with the opening, and remove the plug. Let it drain. This is the step that separates a real fluid service from a pan drop, because the converter holds a large share of the unit's fluid.
- Install a new converter drain plug and torque it to 89 lb-in (10 Nm), then reinstall the housing access plug.
- Install the new filter. Make sure the filter seals are seated correctly on the filter and lubricated with ATF. Ford puts a caution on this: lubricate the filter seals with clean ATF or they may be damaged. A dry seal can roll or tear going into the bore, and a torn pickup seal lets the pump pull air.
- Magnet and gasket. Put the magnet back in its spot in the pan and set the gasket on the pan.
- Install the pan. Start all 16 bolts loosely, then tighten them in a crisscross pattern to 97 lb-in (11 Nm).
- Install the drain plug and torque it to 19 lb-ft (26 Nm).
- Refill through the level plug using the procedure in the next section.
The pan gasket is reusable
This surprises people who came up on cork and paper gaskets. Ford's procedure notes that the 5R55W/S pan gasket is reusable: clean it, inspect it for damage, and replace it only if it's damaged. The same note shows up in the extension housing section: if the fluid pan gasket isn't damaged, it may be reused. In practice I replace it any time the kit comes with one and the old gasket has a flat spot, a cut or a bolt hole that's torn out. A good molded gasket on a clean, flat pan seals fine at 97 lb-in. The leaks I see come from overtightened bolts that dished the pan rail, not from reused gaskets. That's shop experience, not a Ford statement.
The two filter bolts
The Ford torque table I work from doesn't list a separate figure for the two filter bolts. They're small fasteners going into aluminum. I run them down snug with a 1/4-inch drive and stop. If one strips, you're into a thread repair on the valve body, which turns a one-hour service into a much longer day.
The other filter: the solenoid body screen
The main filter isn't the only filter in this transmission. Sonnax points out that on the 5R55 family, the critical parts of the solenoid assembly are the base plate and a small filter that's built into the gasket under the aluminum base plate. They warn that the filter has a silicone bead that doesn't tolerate solvent, so keep it away from the parts washer. They also warn that if the base plate or that filter gets mixed between 5R55 versions, the unit loses Reverse, TCC apply and solenoid oil pressure.
A routine pan service doesn't touch the solenoid body, and it shouldn't. If you do have it off for a solenoid replacement, the parts that go back on have to match the unit. The 5R55N has a reverse pressure switch and its own base plate, and it isn't the same as the W or S.
Refilling a 5R55S with no dipstick
Here's where the job goes right or wrong. The Ford procedure and ATRA Technical Bulletin 746 describe the same basic method, and it depends on fluid temperature.
- Connect a scan tool and watch the TFT PID. Start the engine. Idle should be about 650 rpm.
- Run it until TFT reads 80-120°F (27-49°C). Move the selector slowly through each range, stopping in each one, then put it in Park.
- With the engine running, get the vehicle as close to level as possible on the lift. Ford lists a drive pinion angle gauge (205-025) to help level the vehicle.
- Hold the large drain plug with a wrench and remove the small center level plug with a 3/16-inch Allen key. Let it drain for about one minute.
- If fluid comes out as a thin stream or a drip, the level is correct. If nothing comes out, install the 307-437 fill tool in the pan.
- Push in about one pint of clean MERCON V, remove the gun and let it drain for a minute. If nothing drains, keep adding in half-pint increments until it does.
- Remove the fill tool and reinstall the center level plug at 10 Nm (89 lb-in), the figure in ATRA TB 746's illustration.
- Check operation and look for leaks.
After a service with the converter drained, you'll be starting with the unit well short of full, so the first fill has to happen before the engine runs long. My own habit, not a Ford step: put in a known amount through the fill tool with the engine off to get close, start it, and then finish with the temperature-controlled check above. Never set the final level with the engine off. Fluid drains back from the converter and circuits into the pan and the level reads high.
Watch the fill pressure
Ford's procedure has a note that catches shops with pressure fillers: when using pressurized fill equipment, reduce the pressure to one psi. Higher pressure can push fluid out of the vent, and it then looks like a leak coming from the converter area. ATRA TB 746 describes the Rotunda fluid transporter (307-D465) with no more than 30 psi of shop air on the transporter's hose, adding one pint at a time. The point is the same either way: go slow, in small amounts, and let it drain back before you add more. If a customer comes back with "fluid at the bellhousing" right after a service, think about how the fluid went in before you pull the transmission for a front seal.
How often this service is due
Ford's service information for the 2002 Explorer 5R55W/S calls for a fluid and filter change at 150,000 miles under normal service, and at 30,000 miles under any of these conditions:
- Hot weather above 90°F (32°C) while carrying heavy loads or in hilly terrain.
- Towing a trailer or using a car-top carrier.
- Police, taxi or door-to-door delivery service.
- Extremely dusty conditions or off-road use.
Ford's 2006 Scheduled Maintenance Guide keeps the same 150,000-mile normal interval and the 30,000-mile change for towing and extended idling or low-speed driving. Look at that list honestly and most Explorers qualify. I treat 30,000 miles as the real interval on this unit. On a high-mileage unit with dark fluid, draining the converter at the service gets far more of the old fluid out than a pan drop alone.
Coolers: when they matter and when they don't
A routine service doesn't require cooler work. An overhaul does. Ford's procedure says that when a transmission has been disassembled to install new parts, or when a new or reman unit goes in, a new transmission fluid cooler (in-tank, auxiliary or oil-to-air, if equipped) has to be installed and the cooler tubes cleaned and backflushed. The reason Ford gives is that metal particles, clutch material and band material carried into the cooler are a major cause of repeat transmission concerns. The backflush uses clean ATF only, no solvents. If your pan inspection turns up the kind of debris that means a rebuild is coming, plan the cooler into the quote now.
Reading the pan
This part is my own read, not a published chart, and it's the same read I use on every Ford rear-drive unit. A light gray paste on the magnet is normal wear. Fine black friction material you can feel between your fingers means clutches are wearing. Brass or bronze flakes point to bushings or thrust washers. Steel chunks or pieces of a snap ring mean the unit is coming apart, and no fluid service will save it.
Also know which complaints fresh fluid won't fix. The 5R55S and 5R55W are known for wear in the servo pin bores in the case, which shows up as flares and slips on specific shifts. New fluid can mask it for a few weeks. If the vehicle came in with a shift complaint, a pressure test and a look at the servo bores come next (our servo pin bore guide covers it), not a second fluid service.
5R55W/S service spec summary
| Item | Spec |
|---|---|
| Fluid | MERCON V (Motorcraft XT-5-QM) |
| Pan bolts | 16 bolts, crisscross, 97 lb-in (11 Nm) |
| Pan drain plug | 19 lb-ft (26 Nm) |
| Center level plug | 3/16-inch Allen, 10 Nm (89 lb-in) |
| Torque converter drain plug | New plug required, 89 lb-in (10 Nm) |
| Filter | 2 bolts; lubricate seals with ATF before install |
| Pan gasket | Reusable if undamaged |
| Solenoid body bolts (if removed) | 71 lb-in (8 Nm), in sequence |
| Level check | Engine running, Park, vehicle level, TFT 80-120°F (27-49°C) |
| Fill tool | Ford 307-437 in center of drain plug |
| Pressure fill | 1 psi with pressurized equipment |
| Interval | 30,000 mi severe; 150,000 mi normal |
5R55S filter kit (4.0L and 4.6L, 2002-2010)
The filter and gasket this service calls for, fitted to the Explorer, Mountaineer and Mustang 5R55S. It's sold by our sister store, CoreTransmissionParts.
Shop the part for this fix →Need something else? The 5R55S parts collection has solenoid packs, valve bodies, pumps and rebuild kits.
Need parts for this job?
Our 5R55 parts page carries the filter and pan gasket kit, the 307-437 style fill adapter, MERCON V, solenoid packs and complete overhaul kits for the Explorer, Mountaineer and Mustang units. Checkout is on site.
FAQ
How many bolts hold the 5R55S transmission pan on?
Ford's service procedure calls for removing 16 pan bolts to drop the pan, and two bolts hold the filter. On reinstall the 16 pan bolts are started loosely and then tightened in a crisscross pattern to 97 lb-in (11 Nm).
What is the torque spec for the 5R55S pan bolts and drain plug?
Ford lists 97 lb-in (11 Nm) for the pan bolts and 19 lb-ft (26 Nm) for the pan drain plug. The small center level plug is 10 Nm (89 lb-in), and a new torque converter drain plug goes in at 89 lb-in (10 Nm).
Can you reuse the 5R55S pan gasket?
Yes. Ford's procedure says the 5R55W/S pan gasket is reusable: clean it, inspect it and replace it only if it's damaged. A cut, a flattened section or a torn bolt hole means it gets replaced.
Does the 5R55S have a torque converter drain plug?
The Ford procedure for the Explorer and Mountaineer 5R55W/S includes removing the converter housing access plug and draining the converter through its drain plug, then installing a new drain plug at 89 lb-in. Draining the converter replaces far more of the old fluid than a pan-only service.
How do you fill a 5R55S after a filter change?
Fill from below through the center of the drain plug using the Ford 307-437 fill tool, adding about a pint at a time and then half-pint increments. Set the final level with the engine running in Park, the vehicle level and TFT at 80-120F, until fluid comes out of the level hole as a thin stream or drip.
Related guides
- 5R55S Fluid Type and Capacity
- Ford 5R55S and 5R55W Transmission Problems
- 5R55S vs 5R55W Differences
- 5R55W and 5R55S Servo Pin Bore Wear
- 5R55 Harsh and Delayed Shifts
Sources
- Ford Motor Company service information, "2002 Automatic Transmissions Servicing - Explorer & Mountaineer" (5R55W/S), published by Mitchell Repair Information with Ford illustrations. Backs the 16 pan bolts, two filter bolts, converter drain procedure and new-plug requirement, reusable pan gasket, filter seal lubrication caution, crisscross pan bolt sequence, torque figures (pan bolts 97 lb-in, drain plug 19 lb-ft, converter drain plug 89 lb-in, solenoid body bolts 71 lb-in), the level check and half-pint fill steps, tools 307-437, 303-D104 and 205-025, the 1 psi pressure-fill note, the 150,000/30,000-mile intervals and severe conditions, and the cooler replacement and backflush requirement. Ford/Mitchell service procedure (PDF)
- ATRA Technical Bulletin 746, "5R55N, 5R55S and 5R55W: New Rotunda Tool for Checking Fluid Level and Filling Transmissions" (February 2003). Backs the fluid level and fill plug design with no dipstick or filler tube, the TFT PID and 80-120°F window, 650 rpm idle, the 3/16-inch Allen level plug, adapter 307-437, fluid transporter 307-D465 at a 30 psi maximum, one-pint fill steps and the 10 Nm (89 lb-in) level plug figure. atracom (PDF)
- Sonnax, "Figuring Out the 5R55 Alphabet." Backs the 5R55N/W/S identification differences, the solenoid base plate and gasket-integrated filter, the no-solvent warning on that filter, and the loss of Reverse, TCC apply and solenoid pressure if base plates or filters are mixed. sonnax.com
- Ford Motor Company, 2007 Explorer Owner Guide, Maintenance and Specifications. Backs the 5R55S (VIN code V) on MERCON V XT-5-QM versus the 6R60 (VIN code X) on MERCON SP. Ford owner guide, archived copy (PDF)
- Ford Motor Company, 2007 Mustang Owner Guide, Maintenance and Specifications. Backs the statement that the 5R55S has no transmission fluid dipstick, MERCON V XT-5-QM, and VIN transmission code L. Ford owner guide, archived copy (PDF)
- Ford Motor Company, 2006 Model Year Scheduled Maintenance Guide. Backs the 150,000-mile normal fluid change and the 30,000-mile change for towing and extended idling or low-speed driving. Ford owner guide, archived copy (PDF)