Justin Fivella
May 14, 2014
Photos By: Courtesy AED Motorsports, Steve Raymond, Nate Garland

It's been dubbed the unbreakable one and the last transmission you'll ever buy. Countless people have compared the smoothness of its shifts to laying a hot knife though butter, its brawn to a Sherman tank. It's the most versatile manual transmission on the market and blends the best of the OEM industry with aftermarket performance. Simply put, in the land of manual transmissions, the Tremec T56 Magnum is king.

In 2009, when Tremec debuted the big-boy of stick shifts, it had large shoes to fill—after all, the original T56 is legendary. Thankfully though, Tremec was up to the task. How, you ask? Tremec took the OEM TR-6060 found in such legends as the Shelby GT500, ZR1 Corvette, and ACR Viper, and hot-rodded it to withstand more abuse and more torque, which allows you to rip off high-rpm shifts. Just ask anyone who's driven one and they'll confirm the obvious: If you're looking for one box that can withstand serious abuse and shift with the precision of a Swiss watch, then look no further.

Out with the old and in with the new: Look how much beefier the T56 Magnum is than the outgoing T5. The swap added 57 pounds over the old T5 setup, but the fact the Magnum shifts like glass, has better ratios, and can handle 700 lb-ft of torque more than offsets the additional weight.

The Company, The Myth, The Legend

You'd have to be living under a rock to not have heard of Tremec transmissions, and just as the T56 Magnum is to its competitors, Tremec is the big dog of the manual transmission industry. From countless OEM applications with the older T56s, the current TR-6060, and the new seven-speed TR-6070, to the legendary aftermarket transmissions like the TKO; when it comes to manual transmissions, nobody beats Tremec. In fact, it has been around for 50 years, currently serving a global client base in 70 countries and employs over 1,800 associates.

What makes this box so special? Although the beastly T56 Magnum might be based on the TR-6060 transmission found in the GT500, the Magnum is its own animal, with a unique case, shifter, and other components.

"The T56 Magnum is a completely new transmission, much different from the older T56s and OEM TR-6060s. It's more versatile, with its multiple shifter locations and various electronic hook-ups to suit a wide variety of cars," explained Jim Averill of Tremec Transmissions.

While most T56s are good for 450 lb-ft of torque, the Magnum pushes that capacity to 700 lb-ft and still keeps the shifts as smooth as glass. The Magnum uses triple-cone synchronizers on the First-Fourth gears and double-cone synchronizers on Fifth, Sixth, and Reverse. The syncros have also been narrowed for a stronger, wider gear face that's 6-24 percent wider than a standard T56. The wider gear faces allow for greater torque capacity, high-rpm shift capabilities, and shorter throws. In fact, the Magnum is said to have the shortest shift throws of any Tremec box. It also uses burly 26-spline-input and 31-spline-output shafts to transfer torque into forward motion.

Speaking of throws, the Magnum features a TKO-style moveable shifter for different shifter positions, so it can be moved between multiple projects even if, for example, you decide a classic Mustang is a better fit than your current Fox-body. No worries here. Bring your T56 Magnum—it's welcome at almost any party. The Magnum also gives enthusiasts the ability to use an SFI-approved bellhousing instead of the OEM TR-6060's cast unit. It even employs dual speedometer pickups, one for a mechanical unit and the other for an electronic example. You get the point, it's as stout as it is versatile.

01. The T56 Magnum comes with multiple shifter locations and all kinds of hook-ups to ensure no matter what speedometer, tunnel shape, or OEM connector your car has, the Magnum will slide into place.

02. Here are some of the quality parts that come with the legendary D&D Performance T56 swap kit. In addition to the transmission, the kit comes with an SFI-approved QuickTime bellhousing, all of the required connectors and plugs, along with custom pieces like the Dynotech aluminum driveshaft, and offset cross-member and mount.

03. Here’s a closer look at the stock T5 crossmember against the D&D Performance unit. Note the added offset of the D&D piece to compensate for the added length of the T56 Magnum.

04. Look at the custom Dynotech Engineering aluminum driveshaft compared to the old aluminum FMS unit we removed. Again, notice the difference in length of the Dynotech unit to offset the size of the T56.

05. The Dynotech Engineering driveshafts are some of the best in the industry. We’re talking top-rate components, unbeatable craftsmanship, and a team of engineers behind every unit.

06. Speaking of quality, the Quick Time T56 bellhousing is like Snapple—it’s made from the best stuff on earth. All jokes aside, it’s a high-end unit that’s SFI- approved and has excellent fit and finish.

07. John Rankin of Rankin Performance Machine in Martinez, California, helped us dial in the mating surfaces of the Quick Time bellhousing. Although it didn’t need much, it’s always good to have a quality machine shop like Rankin Performance ensure everything is true.

08. As a wise man once said, always test-fit everything before proceeding with the install. Jack test-fitted the bellhousing to the transmission.

It's All About Ratios

Thankfully Tremec was thorough with the design of the T56 Magnum and took into account the different ratios enthusiasts might want. Believing that one size doesn't fit all, Tremec offers two distinctly different flavors of gear ratios: one wide-ratio and the other a close-ratio. The wide-ratio version (PN TUET11011) has a deep 2.97 First gear with tighter First-Third gears and a land-speed-racing, tall 0.50 Overdrive for Fiesta-like fuel mileage on the super slab. The wide-ratio box is said to be better for drag racing applications with steeper rear gears.

The other available gear set is a close-ratio version (PN TUET11010) with a taller Terminator Cobra-style 2.66 First gear and a shorter 0.63 Overdrive. It's said to be better for road-race applications or closed course roll-racing, it trades wider ratios in the first couple of gears for a tighter spread in the upper gears. Remember though, both Fifth and Sixth overdrive-gears can be mixed and matched by a Tremec dealer for a custom combo of your choice. See how the two ratios compare (Chart 1).

Chart 1
First Second Third Fourth Fifth Sixth Reverse
Wide ratio 2.97 2.10 1.46 1.00 0.74 0.50 2.90
Close ratio 2.66 1.78 1.30 1.00 0.80 0.63 2.90
For reference, the T5 we removed had this spread:
First Second Third Fourth Fifth N/A Reverse
2.95 1.94 1.34 1.00 0.59 2.76

Thankfully Tremec has an online gearing calculator (see accompanying photos) that helped us get a better idea of the gearing in relation to road speed. After careful consideration of our engine's powerband, rev ceiling, desired tire height, and intended use, we decided on the close-ratio combination with the taller 2.66 First. With over 500 lb-ft of torque available in Smog Legal Killer, we felt the wide-ratio box with its 2.97 First was just too short on the street.

The outgoing T5 had a 2.94 First gear, and while it was nice for cutting killer 60-foots, it was so low that it was nearly unusable on the street, causing a double shift just to cross an intersection. Some might think the close-ratio box with its taller First gear will hinder our 60-foots at the track, but we think it's nothing a 500-rpm higher launch won't solve. Instead, the tighter ratios in the upper gears will help keep the Vortech V3 Si-blown 347 in the meat of its powerband instead of falling out of boost between shifts. Stay tuned for track results soon.

A quick search on the Internet proves that there are people on both sides of the fence. Some feel the 2.66 First gear is too tall, while others feel the 2.97 First gear is uselessly low. In reality, while the difference between the two gears is noticeable from the cockpit, the difference isn't that big. To prove our point, we used Tremec's online gear-ratio calculator to get a better idea of the peak speed in each gear using our 27-inch-tall tire and a conservative 6,200-rpm redline. See how they compare (Chart 2).

Chart 2
Max speed (mph) in each gear at 6,200-rpm redline
First Second Third Fourth Fifth Sixth
Wide ratio 44.95 63.58 91.45 133.52 180.43 267.03
Close ratio 50.19 75.01 102.7 133.52 166.9 211.93

This means there's only a 5-mph difference in speed between the 2.66 and the 2.97 First gear ratios at a 6,200-rpm redline. Like we said, the wide-ratio transmission is going to feel more eager out of the hole, while the close-ratio version will have a tighter spread once the car is moving. For reference, Terminator Cobras came with 2.66 First gears in their stock T56s, so it's not like we're talking Bonneville Salt Flat gearing here.