4L80E vs 722.6: Differences and Which One to Choose

The GM 4L80E and the Mercedes 722.6 never came in the same vehicle. One is a heavy-duty American four-speed built out of the TH400 parts bin for pickups and vans; the other is a German five-speed built for luxury cars, Sprinters, and - through the Daimler-Chrysler years - Jeeps, Chargers and 300Cs under the name NAG1. So this is an identification and application comparison, not a "which one is in my truck" question. Here is what each unit actually is, what it holds, what breaks, and which one belongs in your project.

The quick answer

If you are behind a GM V8 in a truck, a van, an LS swap or a race car, the 4L80E is the answer and the 722.6 is not a realistic option. If you own a Mercedes, a Sprinter, a Jeep Grand Cherokee or Wrangler JK, a Chrysler 300C or a Dodge Charger from the NAG1 era, the 722.6 is what you have, and the question is how to keep it alive rather than whether to swap it. The two only genuinely compete in one narrow case: a custom build where you are choosing an overdrive automatic from scratch and you value five ratios and refinement over parts availability and brute simplicity.

What the 4L80E is

The 4L80E arrived in 1991 in GM's C/K trucks and ran through the 2009-plus commercial years in Silverados, Sierras, Suburbans, vans and the Hummer H1. Novak Conversions describes GM's design goal as keeping "as many TH400 parts and designs as possible" while adding an overdrive gear and a lockup converter, which is exactly why it inherited the TH400's reputation. It uses the Chevrolet 90-degree integrated bellhousing and the TH400's 32-spline output shaft.

The name is a spec sheet: four-speed, longitudinal, rated for roughly 8,000 lb GVWR. Gearstar lists the 4L85E variant, introduced in 2002, at 16,500 lb GVWR.

What the 722.6 is

The 722.6 is Mercedes' five-speed 5G-Tronic. Mercedes Blog explains the three names you will see for it: 722.6 is the type number, W5A580 is the classification, and NAG1 - New Automatic Gearbox Generation One - is what Daimler-Chrysler called it. All three refer to the same transmission family.

Wikipedia dates the family from 1996 through 2020 across its variants, and Gearbox List puts the core 722.6 run at 1995-2014. It ended up in an unusually wide range of vehicles: Mercedes C, E, S, CL, SL, ML and G-Class, Chrysler 300C, Dodge Charger and Challenger, Jeep Grand Cherokee, Sprinter vans, Porsche 911, and Jaguar XJ and XK. The Autopian adds Jeep JK Wranglers to that list under the NAG1 name.

Gearing compared

Wikipedia lists the W5A580's total ratio span at 4.327 with an average step of 1.728. The 722.6's first gear is far deeper than the 4L80E's, its steps between gears are smaller, and it has an extra ratio to work with - all of which is why it shifts the way a luxury car is supposed to shift. It also has the unusual feature of two reverse ratios.

The 4L80E's 0.75 overdrive is actually a deeper overdrive than the 722.6's 0.831, so it drops more RPM in top gear relative to direct. But with only four ratios and a big 2.48-to-0.75 spread across them, the 4L80E asks a lot of the converter and the rear axle ratio to fill in the gaps. That is a design choice, not a defect - it is a truck transmission.

Torque capacity

This is closer than most people expect. Diesel Hub lists the 4L80E at 440 lb-ft engine input torque (460 lb-ft for the 4L85E) with 885 lb-ft maximum gearbox torque. Wikipedia gives the W5A580 a maximum input torque of 580 N-m, which is 428 lb-ft - and Mercedes Blog confirms that the "580" in the designation is the safe input torque number in newton-meters.

So the two are roughly in the same input-torque class on paper. Wikipedia also lists a W5A330 variant rated at 330 N-m (243 lb-ft) for smaller engines, and a heavy-duty W5A900 rated at 1,000 N-m (738 lb-ft). Where the 4L80E pulls ahead is in what happens after you exceed the rating: the aftermarket for it is enormous, the internals are TH400-derived and well understood, and a properly built one goes places a 722.6 will not.

Architecture and controls

The 4L80E is a conventional hydraulic-electronic hybrid. A cast valve body full of spool valves, check balls and accumulators does the shifting; shift solenoids A and B, a PWM TCC solenoid and an EPC solenoid tell it when. Almost every shift-quality complaint traces to that valve body, and almost all of it is fixable with the transmission in the vehicle.

The 722.6 works differently. Wikipedia describes three gearsets, three brakes and three clutches, with converter lockup typically engaged in gears 3, 4 and 5. The electronic heart of it is the conductor plate, and this is the single most important thing to understand about this transmission. The Autopian describes it as an electrical component mounted on top of the valve body that houses two speed sensors and six solenoids, carrying the sensing and control signals that let the control unit confirm gear changes by comparing input and output shaft speeds.

What fails on each

4L80E: the intermediate sprag, the center support, the direct and forward clutch packs, the pump bushing and stator support, and valve body bore wear. Mechanical, predictable, and cheap to address. Our 4L80E common failures and heavy-duty build guide walks through how they stack up in a working truck.

722.6: the failures are electrical first, mechanical second.

• Conductor plate. The Autopian notes the contacts degrade over time and the speed sensors fail, which puts the vehicle into failsafe limp-home mode - typically stuck in second gear - with the warning light on. This is the signature 722.6 failure.
• 13-pin connector leak. Mercedes Blog describes the plug adapter's three O-rings as prone to leaking, with the connector tabs typically failing at the same time. The leak lets fluid wick into the harness and can take the control module with it.
• Fluid contamination of the control electronics. Gearbox List notes that transmission fluid reaching the internal control unit causes ECU failure and clogged solenoids, which shows up as jolting shifts.
• Cooler cross-contamination. Gearbox List specifically calls out defective radiators allowing antifreeze into the transmission oil - a coolant-in-ATF failure that destroys the clutches.
• Early mechanical wear items: planetary bearings, the turbine shaft and the K1 freewheel clutch on early builds.

If you want that diagnosis in detail, read our write-up on NAG1 / W5A580 flare and limp mode: conductor plate vs valve body and the companion piece on the 722.6 case connector leak and intermittent solenoid codes.

Fluid, weight and service

The 4L80E is 26-1/4 inches long and runs Dexron VI; Novak lists roughly 254 lb dry and about 268 lb full, while Diesel Hub lists 236 lb dry and 260 lb with fluid. Diesel Hub puts the total fluid capacity around 13.5 quarts.

Gearbox List puts the 722.6 at 76 kg (about 168 lb) and specifies ATF to MB 236.14, with a total capacity of 7.0-9.5 liters depending on variant and a partial change of 5.0-7.5 liters. Service interval is listed at every 60,000 km. That fluid spec is not optional - the 722.6's shift quality and clutch life are tied to it, and generic ATF is a fast way to ruin one.

Gearbox List also gives expected lifespans that are worth quoting for perspective: roughly 500,000 km for the small NAG variants, 400,000 km for the large, and 300,000 km for AMG applications. Maintained properly, this is not a fragile transmission - it is an electrically fragile one.

Which one to choose

Choose the 4L80E if: you are behind a GM engine, you are swapping, you are towing, you are racing, or you simply want the cheapest and most supported overdrive automatic in the American market. It bolts to the Chevrolet pattern, shares the TH400 output shaft, and every part on it is a shelf item. It is also the only one of the two that you can meaningfully build for big power without exotic parts.

Choose the 722.6 if: your vehicle came with it. That is genuinely the main case. It is a good transmission - smooth, well-geared, long-lived when serviced - but it is expensive to source, it needs manufacturer-specific fluid and scan tooling, and swapping one into a non-Mercedes chassis means solving the bellhousing, the controller, the shifter interface and the driveshaft all at once. For a GM-engine build, that effort buys you nothing the 4L80E does not already do.

The honest tiebreaker: the 4L80E wins on parts, cost, strength ceiling and simplicity. The 722.6 wins on refinement, ratio count and factory shift quality. If you already own either one, the right move is almost always to fix what you have.

Rebuilding either one: the parts that matter

For a 4L80E that is already apart, the rebuild kit decides whether it lasts. A master kit puts the frictions, steels, bushings, bearings, washers, sealing rings and gaskets in one box so the job does not stall waiting on a seal.

On the 722.6 side, the equivalent is the 722.6 Master Transmission Rebuild Kit 1996-Up, and if you are only chasing the electrical failure, the 722.6 conductor plate filter and gasket kit covers the service parts that go with that job. Both models are stocked in the transmission rebuild kits collection.

Replace while you're in there

• Torque converter. Never reuse one behind a failed unit on either transmission.
• Filter, pan gasket and correct fluid. Dexron VI for the 4L80E; MB 236.14 spec ATF for the 722.6.
• 722.6 only: the 13-pin connector and its O-rings. Replace it with the conductor plate every time. It is the leak path that killed the last control module.
• 722.6 only: check the radiator/cooler. If coolant ever entered the ATF, the cooler circuit has to be replaced, not flushed.
• 4L80E only: pump bushing and stator support. A worn bushing bleeds line pressure and takes the next clutch pack with it.
• Solenoids on both. Cheap relative to the labor to get back in.
• Speed sensors. Input and output on the 4L80E; on the 722.6 they live on the conductor plate, so a new plate covers them.

Cost and effort framing

The 4L80E is the cheaper unit to own by a wide margin. Cores are common, rebuild kits are commodity parts, valve body upgrades are inexpensive, and a competent DIYer with a bench and a spring compressor can do the whole job in a weekend.

The 722.6 splits into two very different jobs. The conductor plate repair is the friendly one - The Autopian calls it DIY-friendly, sitting on top of the valve body and reachable in about a day's labor without pulling the transmission. A full overhaul is the unfriendly one: the unit is in a tight European chassis, the fluid is a specific spec, and post-repair you generally need a compatible scan tool to clear the control module out of limp mode. Most owners do the conductor plate themselves and farm out the rebuild.

For a broader GM comparison, see 4L80E vs 4L85E.

Frequently Asked Questions

Is the 4L80E stronger than the 722.6?

On paper they are close. Diesel Hub rates the 4L80E at 440 lb-ft engine input torque, and Wikipedia rates the W5A580 version of the 722.6 at 580 N-m, which is about 428 lb-ft. The practical difference is the ceiling: the 4L80E's TH400-derived internals and huge aftermarket let a built unit go well past its factory rating, while a 722.6 has far fewer paths to added capacity outside the factory W5A900 variant.

Can I swap a 722.6 behind a Chevy engine?

It is not a practical swap. The bellhousing, output shaft, shifter interface, wiring and control strategy are all Mercedes-specific, and the transmission is controlled by a module that expects the factory network. You would be solving an adapter, a standalone controller and a driveshaft all at once to end up with a transmission that is harder and more expensive to service than the 4L80E you started with.

What is a conductor plate and why does everyone talk about it?

It is the electrical module that sits on top of the 722.6's valve body. The Autopian describes it as housing two speed sensors and six solenoids and carrying the electrical control signals for the transmission. When its contacts or speed sensors degrade, the transmission drops into limp mode - usually stuck in second gear - which is the single most common 722.6 complaint. The 4L80E has no equivalent single part; its electronics are individual solenoids and an internal harness.

Sources

• Wikipedia - Mercedes-Benz 5G-Tronic transmission (722.6 / W5A580)
• Gearbox List - Mercedes 722.6 (5G-Tronic): specifications, gear ratios, oil
• Mercedes Blog - Guide To Differentiating Between The 722.6, W5A580 & NAG1
• The Autopian - Here's What A "Conductor Plate" Is And Why It Kills So Many Mercedes Vehicles
• Diesel Hub - GM 4L80E, 4L85E Transmission Specs & Ratios
• Novak Conversions - The Novak Guide to the GM 4L80E Automatic Transmission
• Gearstar Performance Transmissions - The Ultimate Guide to the 4L80E Transmission