Way back in the good old Fox Mustang days, 6-speed transmissions were considered exotic and expensive. We never dreamt of having such a transmission in a Mustang. Fortunately, Tremec was contracted to build the now-legendary T56 for the Terminator ’03-’04 Cobra, a car that has also reached legend-status among Mustang faithful.
When that happened, we all fell in love with the T56 when it first landed in a Cobra’s tunnel, and Mustang enthusiasts have had a love affair with 6-speeds ever since. After the original T56’s appearance in the Cobra, however, we didn’t see another 6-speed in a Mustang until the 2007 Shelby GT500. Fortunately, the 2003-2004 Cobra held us over, and it continues to do so. The TR-6060 was Tremec’s response to, “Our customers want better shift quality and increased torque capacity,” says Tremec’s Enthusiast Marketing Director Nate Tovey.
When Tovey uses the word “customers,” he means the automotive Big 3 – Ford, Chrysler, and Chevrolet. Mustang enthusiasts get to reap the benefits of Tremec’s customers, since the aftermarket makes up only a fraction of Tremec’s business.
In this context the Magnum and Magnum XL transmissions are the aftermarket versions of the TR-6060, but more on that later.
We’re here to help clear things up between the TR-6060 and the Magnum transmissions, and make sure you are educated about what’s in your Mustang’s tunnel, or on what transmission you want in the tunnel if you’re looking for an upgrade in the future.
Tovey says the Shelby’s TR-6060 actually started with a new synchronizer design. The synchro assembly was thinner in the TR-6060 compared to the T56. This narrower assembly allowed Tremec to bolster the transmission’s strength.
Thanks to the assembly’s more compact design, the company was able to add surface area to the gears and synchronizers, which in turn added strength. The added strength allowed Tremec to offer manufacturers more torque capacity when compared to the original T56. That’s how the TR-6060 ended up behind the Shelby GT500’s supercharged 5.4L engine – it could take the abuse from the Shelby’s torque. The improved shift quality came from asymmetric clutch teeth in second and third gears; sintered bronze double and triple cone synchronizers were designed to offer quick gear changes with fluidity.
The gear ratios in the original TR-6060 are as follows:
So, as you can see, not really an aggressive double overdrive like what Mustang enthusiasts are accustomed to with a .74 fifth gear and a .50 sixth, and 6th gear in the earliest version is not much more than the overdrive found in our beloved T5. First gear is pretty close to a 2.95 cog that many heads-up racers like to use within a modified T5 transmission to help get them off the line without wheel spin. A run-of-the-mill T5 had a 3.35 first gear, which caused too much wheel spin in Fox Mustangs. If the T5 had been used in the first S197 GT500s, it would have most likely caused the same issue, but the 2.98 first gear in the TR-6060 best bridged the gap between blowing the tires off, and not lugging the engine and clutch at take-off. With a Shelby’s existing torque, a higher-numerically first gear would have too much torque multiplication, thereby causing a copious amount of wheel spin.
Tremec’s Performance Product Engineer Kevin Ryan tells us the gear ratios were revised for the 2010 Shelby GT500 to have more of a double overdrive design. The only ratios that changed were fifth and sixth gear. The fifth gear was changed to a .74 ratio, and the sixth gear to a .50 ratio, giving both gears an overdrive feel to them, hence the double overdrive notation. That helped the GT500’s fuel economy, but also made it long-legged on the highway.
Speaking of long-legged, for the 2013-2014 Shelby GT500, Ford wanted the car to be more of a supercar than in previous years. As we all know, 200-mph is supercar territory, and that’s where Ford wanted the GT500. So, the TR-6060 transmission was geared accordingly. Not only that, but in order to back-up the supercar performance, the 0-60 time needed work, necessitating the use of different ratios yet again.
Everyone drives a different way, and treats a transmission differently so it’s hard to quantify how much a certain transmission will take. Nate Tovey, Tremec
The 2013-2014 Shelby GT500’s TR-6060 ratios are as follows:
Right off the bat you notice the revised 2.66 first gear cog. This ratio was designed to provide a quick 0-60 time. It enabled the GT500 to reach 60 mph in first gear, reducing 0-60 time due to not having to shift into second gear in the process. Also, you can see the transmission still had a double overdrive, but even though the previous GT500s were Ford’s supercar, the 2013-2014 GT500’s 662 horsepower made it possible for the car to attain 200-mph.
Tovey says, “As a transmission’s torque capacity rises, the first gear ratio is numerically lower.” The torque capacity for the TR-6060 in the 2013-2014 GT500 rose, which made it possible for the 2.66 first gear ratio to be used in this application.
When wrapping our heads around this, one thing Tovey talked to us about during the interview process for this story was the fact that many people had to adjust their driving style at the track because of the TR-6060’s remote shifter arrangement. Tovey tells us the fact that people aren’t able to grip-it-and-rip-it with the TR-6060’s shifter arrangement makes it possible for the transmission to live behind a lot of power. If people were able to treat the transmission like they wanted, transmission longevity might come into play. “The best option for a performance application is a direct-shift transmission,” Tovey says. Tremec doesn’t really like to get in too deep when it comes to rating its transmissions’ torque capacities. Transmission longevity largely depends on how you drive.
Magnum and Magnum XL
Okay, so where does the Magnum transmission come into play? In a nutshell, the Magnum is the aftermarket version of the TR-6060. The Magnum is the transmission you can bolt into everything from a ’34 Ford street rod to a Fox Mustang to a Coyote swap car. The Magnum is a jack-of-all-trades transmission. It also masters the art of being the last transmission you’ll ever need.
Many people call it a T56 Magnum, and it’s even labeled that on many parts of Tremec’s website. However, the company is trying to get away from calling it a T56 Magnum because there’s nothing common between the T56 and the Magnum, even though the boxes appear very similar. It’s just that we had a familiarity with the T56 transmission, and Tremec was okay with people calling it a T56 Magnum because of how the T56 was embraced by everyone involved.
“They don’t carry any common parts,” Tovey says. “You can think of a TR-6060 and the Magnum as a T56 2.0.” Tremec took everything it learned from the T56 program and applied it to the Magnum and TR-6060.
The important difference between the TR-6060 and the Magnum is the TR-6060 uses a remote shifter configuration like what we talked about earlier, to keep NVH (Noise, Vibration, and Harshness) concerns to a minimum for manufacturers. The TR-6060 also has an integral bellhousing, cast into the front of the transmission. The Magnum has a conventional bellhousing. The Magnum also uses a slip-yoke 31-spline tailshaft configuration, which is more desirable from a strength and weight standpoint. The TR-6060 uses a bolt on yoke.
At the core of each transmission, the bellhousing, shifter, and driveshaft are the biggest differences between the TR-6060 and the Magnum. Both the TR-6060 and the Magnum are compatible with both an electric speed sensor, or a cable-type arrangement. The 2.66 – 0.50 gear set is the same between the TR-6060 and the Magnum. The torque capacity between the TR-6060 and the Magnum are similar.
“The Magnum is more about providing TR-6060 durability and sophistication in a universal performance application,” Tovey says. The Magnum is built for an incredibly wide variety of applications.
The Magnum XL is simply a Magnum with a longer tail housing so you can bolt it right into a 2005-’14 Mustang, and even a 2015 Mustang since the S550 chassis has changed very little from the 2014 model in terms of transmission tunnel dimensions.
“The original Magnum is modeled after it going into a Fox Mustang platform,” Tovey says.
In other words, the Magnum’s original intent in life was to make our dreams come true; to have a 6-speed in a Fox Mustang. The Magnum XL’s extended tail housing makes it where the shifter position lines up with the 2005-2014 floor pan’s shifter provision. What the Magnum XL gives you is a direct-shift 6-speed in a 2005-15 Mustang.
In a nutshell, if you have skipped to the bottom without reading any of this article, the TR-6060 is the stout 6-speed transmission in your Shelby GT500. The Magnum is the 6-speed transmission you can bolt into your Fox, SN95, new-edge Mustang, or other muscle car, and the Magnum XL is the one you can bolt into your 2005-2015 Mustang.