TorqShift Vs. Allison: Which Heavy-Duty 10-Speed Is Superior?

• March 17, 2023
• Story By
  Mike McGlothlin

If you’re going to offer a diesel engine that turns out 1,000 lb-ft of torque, you better have a transmission that can handle it. With the manual gearbox option now extinct in the heavy-duty pickup segment that means the Big Three have invested millions into their automatic transmission designs. Long gone are the days of the 1960s-based slushboxes equipped with another gear and overdrive. Now the modern automatics found in late-model diesel trucks are computer controlled monstrosities intended to live in everything from ¾-ton pickups to class 6 or 7 medium-duty applications. In particular, the 10-speed 10R140 TorqShift in Ford’s Super Duty and the 10-speed 10L1000 Allison in GM’s HD trucks are some very serious pieces of power-transferring hardware.

Although they weren’t technically co-developed by Ford and GM (as the 10R80 and 10L80 half-ton 10-speed automatics were), both debuted for the 2020 model year, both are built in Ohio and both look similar internally... But which one is stronger and why? And how do they compare to their predecessors (the TorqShift 6R140 and Allison A1000)? Thanks to the transmission dissection work performed by the pros at Randy’s Transmissions, we have the answers to those pressing questions. While we won’t give everything away here, we will say that the Allison name within Chevrolet and GMC trucks isn’t quite what it used to be…

Ford’s 10R140 TorqShift

Ford has been building its own diesel-specific transmissions for decades now. And since the 2003 model year, the company has been using the TorqShift name for its electronically controlled automatic transmissions. The five-speed 5R110W TorqShift was employed behind both the 6.0L and 6.4L Power Stroke (’03-‘10), the six-speed 6R140 Torqshift was used behind the 6.7L Power Stroke from ’11-’19 and now the ten-speed 10R140 Torqshift can be found in ’20-present Super Duty’s equipped with the same engine. The 10-speed automatic features close ratios to perpetually keep the engine as fuel (and emissions) efficient as possible, and eighth, ninth and 10th gears all have overdrive ratios. The gear ratios are as follows:

GM’s 10L1000 Allison

Like Ford’s 10-speed TorqShift, GM introduced its 10-speed Allison for the ’20 model year. The 10L1000 Allison represents a drastic departure from the six-speed Allison 1000 it replaced—namely because the five and six-speed A1000’s were based off of Allison’s modular design from the late 1990s. While the 10L1000 is said to have had oversight from Allison engineers, it is 99.9-percent GM. The 10L1000 Allison, which allows for first gear torque converter lockup, also boasts three overdrive ratios in eighth, ninth and 10th gears. Its gear ratios are as follows:

Transmission Pumps

Per the experts at Randy’s Transmissions, while the 10R140 and 10L1000 aren’t exactly identical, you can tell that two companies took one design and added their own twist to it. The similarities begin with the oil pump. Although the pumps are located on opposite sides of the transmission, they appear to be the same unit. However, the oil pump gear is twice as big on the Torqshift version. And since you can see part of it in the photo above, we’ll go ahead and mention that one area of complete difference between the 10R140 and 10L1000 is the valve body.

F-Clutch Issues

A common cause of wear and failure in the Allison 10L1000 exists in the F-clutch assembly, which is present in both the 10L100 and 10R140. These clutches sit within the main drum (where most components are stacked in either transmission) and, over time, their teeth begin to wear into the drum itself. Within the TorqShift, the F-clutches boast a lot more friction material, more surface area and are also noticeably beefier than the versions employed in the Allison.

Drum Differences

In looking at the main drum of the 10R140 and comparing it with the 10L1000’s, you can see that Ford’s drum is anodized (top) and GM’s isn’t (bottom). Anodizing has long been known to improve wear resistance, but it can also improve the lubrication properties of a metal. With many ’20-newer Allison owners experiencing clutches blowing completely through the drum, we’d venture to guess anodizing is at least part of the reason why the same thing isn’t happening to the Ford drum. For a bit of perspective, when the 10R140’s drum is fully packed it tips the scales at 104 pounds! Further tidbit: the 10R140 weighs 347 pounds in total.

E-Clutch Problems

The E-clutches within the 10R140 TorqShift and 10L1000 Allison are employed during Overdrive, which means they see considerable torque. These clutches also feature minimal surface area. This is a bad combination for a transmission on the receiving end of an engine turning out 1,000 lb-ft (or more) of torque. So far, the general consensus is that E-clutch failure is much more commonplace in the Allison. It’s worth noting here that the apply piston on the E-clutch hub is made of steel on the TorqShift, but aluminum on the Allison.

Better Filtration On The TorqShift

Judging by the size of the internal filter bolted to the 10R140 TorqShift, it has twice the filtering capacity of the one on the Allison 10L1000. This might also help explain Ford’s 150,000-mile service interval for fluid and filter replacement vs. the Allison’s 45,000-mile interval for the same job. The short service interval required for the 10L1000—as well as its small(ish) filter—is a definite surprise to many familiar with the Allison name.

The Verdict: Ford’s 10-Speed Wins