10R80 Fluid Type and Capacity

The two questions I get most about the 10R80 are "what fluid does it take" and "how many quarts do I buy." Both have short answers, and both have a catch that costs people money. The fluid is MERCON ULV and nothing else. The capacity number everyone quotes is a dry-fill number, and it is not what goes back in after a service.

This guide covers the 10R80 in the F-150, Expedition, Navigator, Mustang, Ranger, Explorer and Transit: the exact Ford fluid spec and part numbers, what makes ULV different from the MERCON LV on the shelf next to it, how much fluid a dry unit and a service actually take, and the hot level check that decides whether the number was right. Every source is linked at the bottom.

Recommended 10R80 parts

The right fluid and the filter for a 10R80 service: full synthetic ULV-spec ATF and the filter and pan gasket kit. Secure checkout on site.

Valvoline ULV Full Synthetic ATF Case of 6 for 10R80

$88.99View part

Triax ULV Full Synthetic ATF 1 Gallon, Mercon/Dexron ULV

$79.99View part

Ford 10R80 10-Speed Transmission Filter and Gasket Kit

$57.99View part

The short answer

The fluid: MERCON ULV, and why "close enough" is not

Ford's Motorcraft fluid page lists MERCON ULV for the "8F Front Wheel Drive and 10R Rear Wheel Drive families," under part numbers XT-12-QULV, XT-12-5QULV and XT-12-DULV. Ford's automatic transmission fluid chart puts the 10R80 on ULV from the 2017 model year forward, and the 10R60, 10R80 MHT hybrid and 10R140 in the same ULV column. There is no earlier-fluid exception for the 10R80 the way there is for older units.

The same Motorcraft page says ULV cannot be used in applications that call for MERCON V, MERCON SP, MERCON LV, Type F and several other Ford specs. The fluid chart states the other direction just as plainly: these are unique fluids and must be used where that particular fluid is recommended. It does not work both ways. You cannot use LV where ULV is called for, and ULV is not a universal Ford fluid either.

What the numbers actually say

ULV and LV look the same in the bottle, which is why they get swapped. Ford's own product data sheets show how far apart they are:

At operating temperature, ULV is about 25 percent thinner than LV. At 40 C it is about a third thinner. Cold, the gap is over two to one. That matters because the 10R80's line pressure control, solenoid current and adaptive shift tables were calibrated around ULV's flow. Put LV in and the fluid moves differently through the valve body and the clutch apply circuits. The TCM does not know the fluid changed. It keeps applying the same solenoid commands and then tries to adapt its way around the difference. Transend's install guide for its reman 10R80 puts it bluntly: the wrong fluid "will lead to shift quality concerns and unit failure."

The Motorcraft ULV page also describes it as a high viscosity index fluid with improved shear stability and oxidation resistance. That is the point of it. Ford gets the fuel economy of a thin fluid without the fluid thinning out further as it ages. It also means ULV is a precise product. Mixing it with LV, or adding a bottle of something to it, undoes that.

The two-fluid truck

Here is where a lot of mix-ups actually start. A 4WD 10R80 truck uses two different Ford fluids, and they sit next to each other on the parts list. In Ford TSB 24-2254, the 10R80 bulletin for 2021-2022 F-150, 2022 Expedition and Navigator, 2021-2022 Mustang, 2020-2022 Explorer and 2020-2023 Transit, the parts table lists Motorcraft MERCON LV (XT-10-QLVC in the U.S., CXT-10-LV6 in Canada) for the 4WD transfer case, and MERCON ULV (XT-12-QULV) for the transmission. Same truck, same bulletin, two fluids.

If someone services the transfer case and the transmission on the same visit with one jug, one of them got the wrong fluid. I label the bottles before the truck goes on the lift for exactly that reason.

No additives, no "universal" fluid for the warranty question

Ford's fluid chart carries a caution in capital letters: do not use supplemental transmission fluid additives, treatments or cleaning agents. There are aftermarket full synthetics sold as ULV-compatible, and some are good fluids. If the truck is under warranty or you are chasing a shift complaint, use Motorcraft ULV or a fluid that states it meets MERCON ULV. Do not use a "multi-vehicle" ATF that lists a dozen specs and not ULV by name. If the bottle does not say MERCON ULV, it does not go in a 10R80.

One more trap: the GM 10L80 is the 10R80's co-developed sibling, but GM specifies its own DEXRON fluid for it. A GM ULV bottle and a Ford ULV bottle are not interchangeable just because both say "ULV." Follow the spec name on the bottle, not the acronym.

Capacity: the number everyone quotes, and what it really means

Sonnax, working from Ford service information, states that a 2020 F-150 4x4 needs 13.0 qt (12.3 L) of MERCON ULV after an internal repair. That is a dry fill: empty case, empty converter, empty passages. Transend's reman units ship pre-filled with about 13 qt, and Transend notes that the fill still does not account for the vehicle's cooling system. So on a truck with a cooler and lines, the total system fill is higher than 13 qt.

Ford does not publish one simple "drain and refill" quantity, and there is a good reason. How much comes out depends on how the fluid was removed:

• Pan drop. Most 10R80 factory pans have no drain plug, so the pan comes off. The converter, cooler, lines and case passages keep their fluid. You get back only part of the total fill, and the rest stays in the unit mixed with the new fluid.
• Drain plug (aftermarket pan). Similar to a pan drop, just cleaner and faster.
• Exchange through the cooler lines. Replaces most of the fluid and can take 13 qt or more once you count the overlap needed to flush out the old fluid.
• Rebuild or reman install. Start at the dry fill of about 13 qt, then add what the cooler circuit takes.

The shop rule I use on every one of these: catch and measure what comes out, put that much back in, then set the final level hot. Buy more than you need. Two 6-packs covers a pan drop with room to spare, and it keeps you from running to the parts store with the truck on the lift and the pan off.

Filters are not all the same part

If the pan comes off, the filter should be replaced, and the part varies by vehicle. Ford lists the same pan gasket, HL3Z-7A191-B, in both the F-150 and Explorer bulletins. For the filter, Ford TSB 23-2152 lists HL3Z-7A098-A for the 2017-2020 F-150, 2018-2021 Expedition, Navigator and Mustang, and 2019-2023 Ranger. Ford TSB 21-2046 for the 2020 Explorer, Aviator and Police Interceptor Utility lists a different filter for that platform: L1MZ-7A098-A for the 10R80 and LP5Z-7A098-A for the 10R60. If you are servicing an Explorer, do not grab an F-150 filter just because the transmission name matches.

The hot level check: where the capacity number is proven

The 10R80 has no conventional dipstick tube on most applications. The level indicator is built into the fill plug on the side of the case. Sonnax found that as little as 1 qt (1 L) overfilled causes both overheating and fluid venting on Ford 10-speeds. The usual cause is a unit filled to the top mark cold on the lift that ends up a quart high once it reaches operating temperature. GEARS Magazine reports that low or high fluid level is the leading cause of overheating on the 10R units, which normally run 206-215 F (97-102 C).

The check, per Transend's install guide, which matches the temperatures Sonnax gives from Ford service information:

1. Connect a scan tool and watch TFT (transmission fluid temperature). The reading is only valid at 96-101 C (206-215 F), on a level surface.
2. With the engine running, move the selector through each range, holding about 6 seconds in each, then return to Park.
3. Remove the fill plug and pull the level indicator from the plug.
4. On an indicator marked A and B, the level belongs at the center of the B area. On an indicator marked 1 through 6, it belongs between 4 and 5.
5. Do not overfill. Torque the indicator to 20 lb-ft (27 Nm).

Sonnax adds two cautions. The hatch marks and correct fill point vary by application and model year, so confirm against the service info for the exact vehicle. And some units have a thermal valve, which is one more reason a cold reading tells you almost nothing. Getting a 10R80 to 206 F takes a real drive, not a few minutes of idling in the bay.

What wrong fluid or wrong level looks like

• Overfilled: fluid spitting from the vent, a burnt smell after a tow, high TFT readings on a truck that used to run normal temperatures.
• Underfilled: delayed engagement when hot, flare on upshifts, converter clutch slip codes. Check the level hot before you condemn a solenoid or a valve body.
• Wrong fluid (LV or a multi-vehicle ATF): harsh or delayed shifts that show up right after a fluid service and do not adapt out. The fix is to get the unit back on ULV, not to keep relearning it.

Those symptoms overlap with real hard failures, so do not stop at the fluid. Our 10R80 harsh and delayed shift guide covers the TSBs and the adaptive relearn, and the 10R80 fluid change cost breakdown covers Ford's 150,000-mile interval and what a proper service should include.

Need parts for this job?

ULV-spec fluid, the 10R80 filter and gasket kit, and drain-plug pan kits are all on our 10R80 parts page, with checkout on site.

FAQ

What transmission fluid does a 10R80 take?

Motorcraft MERCON ULV, Ford part number XT-12-QULV for a quart or XT-12-5QULV for a 5 qt jug. Ford's fluid chart lists ULV for the 10R80 from 2017 on. Any aftermarket fluid must state it meets MERCON ULV by name.

How many quarts does a 10R80 hold?

Sonnax, citing Ford service information, gives 13.0 qt (12.3 L) of MERCON ULV for a dry 2020 F-150 4x4 unit after internal repair, and the cooler circuit adds to that. A pan drop takes much less because the converter and cooler keep their fluid, so measure what drains out, refill that amount and set the final level hot.

Can I use MERCON LV in a 10R80?

No. Ford's Motorcraft data says the fluids are not interchangeable, and the data sheets show LV at 6.0 cSt at 100 C against 4.5 cSt for ULV. LV is correct for the 4WD transfer case on many of these trucks, which is where most mix-ups start.

How do you check 10R80 fluid level?

With a scan tool, bring TFT to 96-101 C (206-215 F) on level ground, cycle through each range about 6 seconds with the engine running, then pull the level indicator from the fill plug. The level belongs at the center of B, or between 4 and 5 on a numbered indicator. Torque it back to 20 lb-ft.

What happens if you overfill a 10R80?

Sonnax found that as little as 1 qt over full causes overheating and fluid venting on Ford 10-speeds. The usual cause is filling to the top mark cold, which leaves the unit a quart high once it reaches operating temperature.

Related guides

• 10R80 Filter and Pan Service Guide
• 10R80 Fluid Change Cost
• 10R80 Common Problems and Fixes
• Ford 10R80 10-Speed Transmission Guide
• 10R80 Harsh and Delayed Shifts
• 10R80 vs 10R60 Differences