6L80 vs 10R80: Differences and Which One to Choose

These two never came in the same truck. The 6L80 is a GM six-speed. The 10R80 is Ford's ten-speed. But they are more closely related than most people realize, and comparing them is genuinely useful if you are deciding what to build, what to swap, or what you are actually looking at on a stand.

The connection is that the 10-speed was a joint program. Diesel Hub explains that Ford and GM jointly developed it, with Ford leading the 10-speed design and GM leading the 9-speed, under an agreement that let Ford use GM's 9-speed and GM use Ford's 10-speed. That is why GM's 10L80 and Ford's 10R80 are essentially the same transmission wearing different badges - and why the honest GM-versus-Ford version of this comparison is 6L80 against 10R80's twin.

The short version

• 6L80 - GM Hydra-Matic six-speed, RPO code MYC, clutch-to-clutch, integrated adaptive controller in the valve body. 2006 up, gas V8 GM trucks, SUVs and performance cars.
• 10R80 - Ford ten-speed, co-developed with GM, four planetary gearsets, three overdrives, TCM controlled. 2017 up, F-150, Mustang, Expedition, Ranger, Transit and Navigator.

Gearing: six ratios versus ten

The Novak guide to the GM 6L80 and 6L90 lists the 6L80 at a 6.04 spread: 4.02 first, 2.36 second, 1.53 third, 1.15 fourth, 0.85 fifth, 0.67 sixth, 3.06 reverse. Gearstar gives the same set to three decimals and notes the layout is four underdrive gears and two overdrives with no direct-drive ratio.

F150hub lists the 10R80 ratios as 4.69 first, 2.98 second, 2.14 third, 1.76 fourth, 1.52 fifth, 1.27 sixth, 1.00 seventh, 0.85 eighth, 0.68 ninth, 0.63 tenth, and 4.86 reverse. Seventh is the direct-drive gear, and eighth, ninth and tenth are all overdrives.

Read those two lists side by side and the difference is obvious. The 10R80 launches on a deeper 4.69 first, then steps through ratios that are much closer together, and finishes on a taller 0.63 top gear against the 6L80's 0.67. It is a wider spread covered in smaller increments. Diesel Hub notes the 10-speed's deep first gear and three overdrives are the core of the design, and that despite ten forward gears the unit is comparable in size to a traditional six-speed automatic.

What that buys in practice: quicker acceleration for a given axle ratio, less engine speed change per shift, and better ability to hold the engine near its efficiency sweet spot. What it costs: complexity, more clutches and brakes to wear, and a valve body with far more to go wrong in it.

Torque capacity and weight

• 6L80: Novak lists maximum input torque at 440 lb-ft with output torque reaching 664 lb-ft. Gearstar independently lists a 440 lb-ft input rating and notes it is rated for up to 8,600 lbs gross vehicle weight. Dry weight is approximately 195 lbs per Novak, up to about 230 lbs full, on Dexron VI with a 10 to 12.6 quart fill.
• 10R80: F150hub lists a nominal maximum torque capacity of 800 N-m, weight around 235 lbs for rear-wheel-drive and about 230 lbs for four-wheel-drive, an aluminum case, MERCON ULV fluid (Motorcraft XT-12-QULV), and a 13 quart capacity. Diesel Hub puts the max torque capacity at roughly 590 lb-ft, which is the same 800 N-m figure converted, and lists approximately 13 quarts and an operating temperature of 206-215F.

So the 10R80 carries roughly 150 lb-ft more input torque than a 6L80 in a package that weighs about the same. That is the headline. Ford-Trucks.com, quoting Ford technician Mayson Dunsford, gives the family ratings directly: the 10R60 is rated to 443 lb-ft (600 Nm), the 10R80 to 590 lb-ft (800 Nm), and the 10R140 was originally rated to 1,050 lb-ft in the 2020-up Super Duty.

Architecture and control

The 6L80 is a conventional clutch-to-clutch six-speed. Gearstar describes it as a microprocessor-controlled electric-over-hydraulic unit that shifts clutch-to-clutch with no bands at all, and Novak notes the transmission control module is an adaptive-learning 32-bit computer integrated into the valve body, communicating with the engine controller over CAN. Novak also points out a practical feature: removable bellhousings and tailhousings for interchangeability across the GM 90-degree engine family, which is why the 6L80 is a favorite for swaps.

The 10R80 packs four planetary gearsets, six clutches, two brakes and four clutch packs into that same envelope. F150hub notes it also carries an integrated electric transmission fluid pump so the vehicle can run stop-start, plus selectable Tow Haul, Sport and Normal modes. Diesel Hub cites upshift speeds in gears one through four that are 26 to 36 percent quicker than a Porsche PDK dual-clutch, which is a fair indicator of how aggressively the control strategy is tuned.

Applications: which one is in front of you

6L80. Gearstar notes the RPO code is MYC and points to the 18-bolt case as an out-of-vehicle identifier. Novak lists factory applications from 2006-2016 including Chevrolet Corvette, Avalanche, Silverado, Suburban and Tahoe, Cadillac XLR, STS and Escalade, GMC Sierra and Yukon, the H2 and the Pontiac G8. Gearstar adds the 2010-2015 Camaro and the 2017 Chevrolet SS.

10R80. Ford-Trucks lists it debuting in the 2017 F-150 with the 3.5L EcoBoost before moving to all 2018-up F-150s, then appearing in 2018-up Mustangs, 2018-up Expeditions, 2019-2023 Rangers, some 2020-up Explorers including hybrids and Police Interceptors, 2018-up Transits, and 2018-up Lincoln Navigators. Diesel Hub notes GM's 10L80 debuted first, in the 2017 Camaro ZL1.

If you have a Ford, the sibling that matters for parts is the 10R80. If you have a GM and someone told you they put a "10R80" in it, they almost certainly mean a 10L80 - the GM-badged version of the same design.

Known weak points on each

10R80. Ford-Trucks, quoting Dunsford, names three main failure points and two lesser ones:

• CDF drum. On earlier 10R80s a poorly designed bushing inside the CDF drum slides out of position, letting a Teflon seal fail and causing pressure loss. Ford revised the bushing, and Dunsford notes that vehicles built after 12/23/2022 likely already have the revised drum from the factory. If yours does not, insist on the revised part in any rebuild.
• Outer shell. The outer shells are aluminum, which is softer than the steel clutches running against them, so clutches can stick into divots worn in the shell and cause strange shifts. Ford's fix was to anodize the shell to harden it - the revised part is black rather than silver.
• Valve body. Fine metallic contamination collecting in the valve body pushes it out of spec. Dunsford recommends replacing the valve body any time a 10R transmission is rebuilt.
• Torque converter shudder, which Dunsford calls much less common on the 10R80 than on the older 6R80 but still an occasional issue.
• Gear driven pump noise, a less common complaint.

Ford-Trucks also notes that 2017-2020 calibrations are more prone to gear-hunting in pursuit of fuel economy, while 2021-up units shift more consistently, and Dunsford specifically advises against buying a used 10R80 out of a salvage yard because you may simply acquire another early unit waiting to fail.

6L80. The 6L80's failure list is shorter and older, which is a real advantage. Its known problem areas concentrate in the clutch and steel packs, the wave plate, the valve body and control unit, and the torque converter. It has been in the field since 2006, the failure modes are thoroughly documented, and parts supply is excellent.

Which one to choose

If you are building a GM vehicle or an engine-swap car, choose the 6L80. Novak's point about removable bellhousings and tailhousings interchangeable across the GM 90-degree engine family is not a small thing - it is what makes the 6L80 adaptable into everything from Jeeps to hot rods. It is lighter than a 10R80, it is simpler, its parts are cheap and everywhere, and its 440 lb-ft input rating covers the majority of naturally aspirated and mildly boosted V8 builds.

If you own a 2017-up Ford, you already have the answer and the question is how to keep it alive. The 10R80 drives better than a 6L80 in every measurable way, but it needs the right fluid (MERCON ULV per F150hub, not a generic ATF), the revised CDF drum, and a clean valve body. Build it properly with a 10R80 overhaul rebuild kit, address shift quality with a 10R80 shift kit, and keep a 10R80 pressure control solenoid in mind if pressure control is your complaint.

If you are chasing maximum torque capacity in a similarly sized package, the 10R80 wins on paper. 590 lb-ft versus 440 lb-ft at roughly the same weight is a decisive number. But swapping a Ford ten-speed into a GM vehicle is a controls and packaging project, not a bolt-in, and GM's own 10L80 is the same transmission with the correct bellhousing and network for a GM drivetrain. If the goal is ten speeds behind an LS or LT, the 10L80 is the sane path.

If you want six speeds with the least complexity to go wrong, the 6L80 is still a very good answer. Fewer clutches, fewer planetaries, no CDF drum to revise, no integrated electric pump, and two decades of accumulated repair knowledge. Build one with a 6L80 master rebuild kit with overhaul gaskets.

Replace while you are in there

On a 10R80:

• The revised CDF drum bushing, and the CDF drum shaft, if the unit predates the factory revision
• The anodized outer shell - the black one, not the silver one
• The valve body, which Dunsford recommends replacing on every 10R rebuild
• The torque converter, every time
• All frictions, steels and seals as a complete set
• MERCON ULV fluid only, at the 13 quart capacity F150hub lists
• The latest TCM calibration, since Ford-Trucks notes the software has been updated repeatedly and 2017-2020 units are the worst offenders for gear hunting

On a 6L80:

• All frictions and steels as a matched set
• The wave plate, which is the classic 6L80 failure
• Full seal, bushing and thrust washer kit
• Torque converter, and Dexron VI only
• Internal filter and pan gasket
• Valve body inspection or a reman unit if shift quality was the complaint

Match parts in the rebuild kit collection and the shift kit collection.

Cost and effort framing

These are not equally difficult jobs, and pretending otherwise is how people get hurt. A 6L80 rebuild is a well-trodden path: clutch-to-clutch, one controller, a valve body most rebuilders have seen hundreds of times, and a parts supply that has been mature for years. The cost drivers are the friction and steel packs, the torque converter, the wave plate, the control unit, and machine work if the pump or stator support is worn.

A 10R80 rebuild is a bigger project. Four planetary gearsets, six clutches, two brakes, four clutch packs, an integrated electric pump, and a valve body that Ford-Trucks' source says should simply be replaced rather than cleaned. The cost drivers are the clutch and steel packs, the torque converter, the valve body, the CDF drum and shaft, the outer shell, and the specific fluid. Labor is the dominant share on either unit, which is why the "while you are in there" list is not optional - the second teardown costs far more than the parts you skipped the first time.

For a deeper look at the two ten-speeds and what actually interchanges between them, read 10L80 vs 10R80: what GM and Ford share, what differs, and what interchanges. For the GM-to-GM version of this decision, see 6L80 vs 10L80: differences, strength and swap reality. And if you are already dealing with the CDF drum, our guide to 10R80 and 10L80 CDF drum failure covers the symptoms and the fix.

Frequently Asked Questions

Can you put a 10R80 behind an LS or LT engine?

It is a controls and packaging project, not a bolt-in. Diesel Hub explains the 10-speed was jointly developed and that GM's own version is the 10L80, which already carries the correct interface and network for a GM drivetrain. If the goal is a ten-speed behind a GM engine, the 10L80 is the version to source. Novak notes the 6L80 is the one with removable bellhousings and tailhousings for interchangeability across the GM 90-degree family, which is why it remains the easier swap.

Is the 10R80 stronger than a 6L80?

Yes, on input torque. F150hub lists the 10R80 at 800 N-m nominal maximum, which Diesel Hub gives as roughly 590 lb-ft, while Novak and Gearstar both rate the 6L80 at 440 lb-ft input. And the 10R80 does it at about the same weight - roughly 230-235 lbs versus 195 lbs dry for the 6L80. The 10R80 is also considerably more complex, so more capacity comes with more to maintain.

Which 10R80 years should I avoid?

Ford-Trucks reports that 2017-2020 calibrations are more prone to gear hunting in search of fuel economy while 2021-up units shift more consistently, and that vehicles built after 12/23/2022 likely have the revised CDF drum bushing from the factory. Their source also advises against buying a used 10R80 from a salvage yard, because you risk acquiring another early unit with the original drum still in it.

Sources

• Diesel Hub - Ford 10R80 and GM 10L80 10 Speed Transmission Specs and Gear Ratios
• F150hub - Ford 10R80 10 Speed Transmission Specs & Ratios
• Ford-Trucks.com - Common Problems With the Ford 10R80 10-Speed Transmission Explained
• Novak Conversions - The Novak Guide to the GM 6L80 & 6L90 Automatic Transmissions
• Gearstar - 6L80E Transmission Specs and Identification