5R55W Explorer Fluid Change: Type, Capacity and Cost

A fluid change on a 2002-2005 Explorer or Mountaineer with the 5R55W looks like any other pan drop until you go looking for the dipstick. There isn't one. There is no fill tube either. Everything goes in and comes out through a two-piece plug in the bottom of the pan, and the level is set by temperature with a scan tool, not by a mark on a stick. That one design choice is why so many of these trucks are running a quart or two low, and why so many quick-lube "top offs" never happened at all.

This is the procedure I use, with Ford's fluid spec, capacity, torque values and service intervals, plus what the job actually costs in parts if you do it yourself.

Recommended 5R55W parts

The filter kit, MERCON V and fill adapter for a complete Explorer 5R55W fluid service. Secure checkout on our site.

5R55W/5R55S Transmission Filter and Pan Gasket Kit

$46.99View part

Motorcraft Mercon V ATF - Case of 12 Quarts (XT5QMC)

$173.99View part

Ford 5R55W/5R55S ATF Fill Adapter (OTC 6604 / 307-437)

$15.99View part

Which Fluid: MERCON V, Nothing Else

Ford's service data lists one fluid for the 5R55W/S in the Explorer and Mountaineer: MERCON V, Motorcraft part XT-5-QM in quarts or XT-5-DM in bulk, with a flat warning that any other transmission fluid could result in transmission damage [1]. Motorcraft's current ATF chart still puts the 5R55N/W/S family in the MERCON V column and lists the quart as XT-5-QMC [2]. That same chart carries a caution that matters on high-mileage trucks: Ford says not to use supplemental transmission fluid additives, treatments or cleaning agents [2]. If a shop wants to sell you a bottle of "shift conditioner" with the service, pass.

Two fluid mix-ups I see on these trucks:

• MERCON LV. The later 6R60 that replaced the 5R55 in the 2006 Explorer runs a different spec. Do not assume "newer Ford fluid" is an upgrade for the 5R55W. Stick with what the service data calls for [1].
• Transfer case fluid. On 4WD and AWD trucks the transfer case is a separate job with its own fill plug. Ford lists plain MERCON ATF (XT-2-QDX) for the transfer case at 2.6 pt (1.25 L) AWD or 3.0 pt (1.4 L) 4WD [1]. Don't let anybody pump the transmission through the transfer case fill or vice versa.

Capacity: 12.6 Quarts, but That Is Not What You Buy

Ford's capacity for the 5R55W/S is 12.6 quarts (12.0 L), and Ford adds a note worth taking literally: capacities are approximate, and the correct level is determined by the fluid level check procedure, not by the amount added [1]. In other words, never pour in a number. Pour in until the check plug tells you it is full.

How much comes out depends on how far you go. A plain pan drain leaves the converter, cooler and lines full. The 5R55W has an advantage most modern units don't: the torque converter has its own drain plug, reached through an access plug in the bottom of the bellhousing, and Ford's service procedure drains it every time [1]. Pan plus converter gets most of the old fluid out in one service, so plan on buying close to a full case. Jasper Engines & Transmissions, which ships remanufactured 5R55N/S/W units, describes the pan alone as holding roughly eight quarts when it first reaches the standpipe on a dry unit, with the remaining four quarts going in after the unit reaches operating temperature and the cooler circuit opens [6].

Item	Ford spec
Fluid	MERCON V (XT-5-QM / XT-5-DM) [1]
Total capacity	12.6 qt (12.0 L), approximate [1]
Level check temperature	81-120°F (27-49°C) TFT, engine idling in Park [1]
Pan bolts (16)	97 lb-in (11 Nm), crisscross sequence [1]
Transmission drain plug	19 lb-ft (26 Nm) [1]
Torque converter drain plug	89 lb-in (10 Nm), new plug required [1]
Center level plug	89 lb-in (10 Nm), 3/16 in. Allen [3]
Fill adapter	Ford/Rotunda 307-437 [1]

First, Confirm It Is a 5R55W (or an S)

Sonnax puts the 5R55W in the 2002-2003 Explorer and Mountaineer, giving way to the 5R55S in 2004-2005 models [4]. The changeover tracked build date more than model year, but for a fluid change it doesn't matter: Ford's servicing data covers the W and S together with the same fluid, capacity and procedure [1]. It only matters when you start buying hard parts. The filter, pan gasket and fill adapter are shared.

Step-by-Step: Ford's Drain, Filter and Refill

Tools and parts

• Scan tool that reads the TFT PID (any tool with Ford enhanced transmission data)
• 3/16 in. Allen key for the center level plug, and a wrench to hold the larger drain plug while you turn it
• Fill adapter 307-437 (or the OTC equivalent) and a suction gun or low-pressure pump
• New filter, pan gasket if yours is damaged, and a new torque converter drain plug
• About 12 quarts of MERCON V

Drain

1. Raise and support the truck. Remove the pan drain plug and drain the pan, then remove the 16 pan bolts, pan and gasket [1].
2. Remove the two filter bolts and discard the filter. Clean the pan and the magnet [1]. Look at what's on the magnet before you wipe it: fine gray paste is normal wear, bronze flakes or steel chunks are not.
3. Remove the converter housing access plug and the converter drain plug, and let the converter drain. Ford requires a new converter drain plug to prevent leakage [1]. Tighten it to 89 lb-in and reinstall the access plug.

Filter and pan

4. Lubricate the filter seals with clean ATF and make sure they are seated on the filter. Ford's caution is blunt: dry seals can be damaged on install [1].
5. Install the filter, the magnet, and the pan gasket. Ford calls the gasket reusable if it cleans up and inspects good; replace it if it is torn or crushed [1].
6. Start all 16 bolts by hand, then tighten them in a crisscross sequence to 97 lb-in. Install the drain plug at 19 lb-ft [1]. These are inch-pound bolts in a stamped pan; a ratchet and enthusiasm will warp the flange and you will be chasing a weep forever.

Fill

7. Hold the large drain plug with a wrench and remove the small center level plug with the 3/16 in. Allen key. Thread fill adapter 307-437 into the center of the drain plug [1].
8. Pump in clean MERCON V. Ford's procedure uses an oil suction gun in roughly one-pint shots [1]. If you use pressurized fill equipment, Ford says to drop the pressure to one psi; higher pressure can push fluid out of the vent, where it will look like a leak from the converter area [1]. ATRA's bulletin on the Rotunda fluid transporter for these units describes the same plug-and-adapter setup, filling a pint at a time and watching for drain-back [3].
9. With the pan drained and the converter empty, the first fill stops at the standpipe long before the unit is full. That's the Jasper point: the pan shows "full" at roughly eight quarts, and the rest goes in after the fluid is circulating and warm [6].

Setting the Level: The Part Everyone Skips

This is the check that decides whether the job was done right. Ford's procedure [1]:

1. Connect the scan tool and monitor the TFT PID. Start the engine; idle should be about 650 rpm.
2. Run the engine until TFT reads between 81 and 120°F (27-49°C).
3. Move the shifter slowly through each gear, stopping in each, then back to Park.
4. Raise the truck and get it as close to level as possible. Ford lists a drive pinion angle gauge (205-025) to help; on a lift, at least get the pan level side to side.
5. With the engine running in Park, remove the center level plug and let it drain for about a minute.
6. If fluid comes out as a thin stream or a drip, the level is correct. If nothing comes out, add fluid in half-pint increments until it starts to drain, wait a minute, and recheck.
7. Reinstall the level plug and torque it (89 lb-in per ATRA's bulletin figure [3]). Lower the truck and check for leaks.

Two things go wrong here. The first is temperature. Above the window, the fluid has expanded and you will set it low; the truck will then neutral out in hard left turns or on a steep driveway. Jasper's division manager calls out that exact complaint, along with slipping, as the common result of low fluid on these units [6]. The second is reading the plug on a unit that is foaming. Sonnax notes the 5R55N, W and S are prone to foaming the fluid in the sump from excess exhaust and valve body wear, which gives fluid out the vent and improper fill indications [5]. If the fluid at the plug looks pink and frothy instead of clear red, the level reading is meaningless, and the real problem is internal. Topping it off makes it worse.

How Often: Ford's Interval vs. Real Explorers

Ford's normal-service interval for the 5R55W/S is fluid and filter at 150,000 miles. The interval drops to 30,000 miles for hot weather above 90°F, heavy loads or hilly terrain, towing or a car-top carrier, police, taxi or delivery use, and dusty or off-road conditions [1]. Read that list again with an Explorer in mind. These trucks tow campers and boats, haul families up mountain grades, and spend summers in heat. Very few of them are actually on the normal schedule.

On a truck past 150,000 miles that has never been serviced, the usual question is whether changing the fluid now will "make it fail." A drain and fill with the correct fluid does not damage a healthy transmission. What happens is that a unit already slipping on worn bands or worn servo bores gets noticed after the service, because now someone is paying attention. Old fluid doesn't hold a failing unit together; if it comes out burnt, diagnose the real problem.

What It Costs

Parts for a full pan-and-converter service at our prices:

Part	Price
5R55W/5R55S filter and pan gasket kit	$46.99
Motorcraft MERCON V, case of 12 quarts (XT5QMC)	$173.99
5R55W/5R55S ATF fill adapter (OTC 6604 / 307-437), if you don't own one	$15.99
New torque converter drain plug	Ford dealer counter item

So a DIY service runs a little over $220 in parts with genuine Motorcraft fluid, plus the fill adapter once. A shop will add labor at its own rate. When you get a quote, ask three questions: Are you draining the converter? Are you using MERCON V? Are you setting the level at the check plug with a scan tool on TFT? A shop that answers "we just pull the pan and fill it up" is going to hand the truck back low.

FAQ

What transmission fluid does a 2002-2005 Explorer 5R55W take?

Ford specifies MERCON V, Motorcraft XT-5-QM in quarts, for the 5R55W and 5R55S in the Explorer and Mountaineer. Ford warns that any other fluid could damage the transmission, and Motorcraft's chart also says not to add supplemental additives or cleaners. The transfer case on 4WD and AWD trucks is separate and takes MERCON ATF.

How many quarts does the 5R55W hold?

Ford lists 12.6 quarts (12.0 L) total, and says the capacity is approximate and the level must be set with the check plug procedure. Because the converter has its own drain plug, a pan-and-converter service replaces most of that, so buy close to a full 12-quart case.

How do you check the fluid level on a 5R55W with no dipstick?

Run the engine with a scan tool on the TFT PID until fluid temperature is 81-120 degrees F, shift slowly through every gear, then put it in Park with the truck level. With the engine running, remove the small center plug in the pan drain plug using a 3/16 in. Allen key. A thin stream or drip means it is full; if nothing comes out, add fluid a half-pint at a time until it does.

How often should the 5R55W fluid be changed?

Ford's normal interval is 150,000 miles, and its severe-service interval is 30,000 miles for towing, heat above 90 degrees F, heavy loads, hills, or dusty and off-road use. Most Explorers fit the severe list, so 30,000 miles is the realistic interval.

How much does a 5R55W fluid change cost?

Doing it yourself, parts run a little over $220 with a filter and gasket kit and a 12-quart case of Motorcraft MERCON V, plus a fill adapter if you do not own one. Shop labor is added on top at the shop's rate. Make sure the quote includes draining the converter and setting the level at the check plug.