T-56 Transmission Guide


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Story By Tom Suddard • Photos Courtesy Tremec

Which Flavor of the Legendary T-56 Transmission Fits Your LS Swap–and Your Budget?

Want to see my 4G63-swapped AW 11? How about my EF9 fitted with a B16A engine and transmission? Oh, and you’ll love my AE86.

Confused? We don’t blame you. Car dorks have been tossing around engine and chassis codes forever, and unless you’re a devoted fan of a particular car (hello, E30 BMW lovers), odds are it’s all gibberish to you.

But we’ve got one code you’re guaranteed to know: T-56. It’s the basic designation for the gold standard in domestic six-speed, rear-wheel-drive, manual transmissions. You can’t enter a forum or a salvage yard without hearing those three characters discussed with hushed awe and respect.

But not all T-56s are created equal, and what may seem like a great bargain might actually be the opposite. To get to the bottom of this aluminum-cased wonder, we roped in the experts at American Powertrain. The T-56 is their bread and butter, and it doesn’t hurt that they’re also the world’s largest Tremec dealer.

Background and Evolution

To understand the T-56’s popularity, let’s start with its birth. It was originally designed and built by BorgWarner for the 1992 Dodge Viper. A year later GM started using it in the Camaro Z28 and Pontiac Trans-Am. Initial reports? It was a tough, modern gearbox.

Tremec bought BorgWarner’s manual transmission business in December 1996, and since 1998 the T-56 has been built by Tremec. Despite their new mommy, internally the transmissions are identical.

The T-56 has been primarily associated with GM products. In addition to GM’s F-bodies, this transmission has also made appearances in the Chevy Corvette, Pontiac GTO, Cadillac CTS-V and Chevy SSR, but that’s just the tip of the iceberg. By American Powertrain’s count, there are 39 flavors of T-56 in the world, not counting its later offshoots, the TR-6060 and T-56 Magnum.

Most of those variants are indeed found in GM cars, but not always. Aston Martin and, yes, Ford, have also used the box. In a world that seems to be more and more polarized, at least Ford and Chevy fans can agree on the T-56.

Why is this transmission, out of all the gearboxes ever made, so popular? There are a few reasons: For one, the transmission was built in fairly large numbers. It’s also reasonably light, features two overdrive gears, can handle a lot of torque, and easily fits today’s most commonly swapped engine, Chevy’s LS small-block V8.

All of this adds up to another reason to love the T-56: lots of aftermarket support. No matter what you want to do with, in, on, or around a T-56, there’s somebody offering a bolt-on solution.

What about the TR-6060? It was designed as a T-56 successor, with the goals being smoother gear changes and the ability to handle even more torque. As a result the TR-6060 features bigger gears and bearings, better shifting hardware, and a new synchronizer arrangement. By 2008 it had superseded the T-56 on showroom floors, and it can be found in applications like the Dodge Viper, Dodge Challenger, and every current GM muscle car except the Corvette. Unfortunately, the TR-6060 carries a relatively high cost and lacks availability on the used market.

The T-56 evolutionary tree isn’t limited to the TR-6060, though. Another branch leads to the Magnum. Here’s the CliffsNotes summary: all the benefits of the TR-6060 but designed for aftermarket customers, meaning it fits wherever a T-56 will. Two versions are available: GM and Ford. The GM box is a bolt-in replacement for the 1998–2002 F-body, while the other is designed for the 2003-’04 Ford Mustang. For greater flexibility, both versions of the Magnum feature multiple shifter locations and two different speedometer inputs.

Tremec also offers the Magnum XL. It’s longer than the standard Magnum and was originally intended for the S197-chassis Ford Mustang.

SOURCES

American Powertrain: americanpowertrain.com

Tremec: tremec.com

HOW TO CHOOSE A T-56

So, you’re sold on a T-56 for your next swap. How do you pick one? Whether you’re junkyard scrounging or ordering online, our ID chart should help you pick a transmission that will match your engine and provide the proper gear ratios. To ID the particular T-56 transmission at hand, simply look at the tag bolted to the left side of the box.

But first, let’s walk through a few T-56 swap scenarios. Since most T-56s are fitted behind some variation of GM’s LS V8, we’ll assume that our hypothetical build is going to use one as well.

OPTION 1: Buy an LT1 T-56 and then convert it for use with your LS.

This method used to be all the rage, and the reason was simple: money. The 1993-’97 Camaro Z28 and Trans-Am are powered by the older LT1 V8 rather than the later, more desirable LS1.

“The biggest issue with the LT-1 is the pull-style clutch setup,” says Matt Graves of American Powertrain. “This gave them a very short input shaft and shallow bell housing that will not work with LS engines. In turn, this requires an LS1 front input shaft conversion so you can run a bearing retainer for an internal-style hydraulic clutch.”

Why isn’t this the best option? A few reasons. First and foremost, the parts are hard to find, and the newest LT1 T-56 is still 21 years old at this point. Tremec would rather sell new transmissions than parts for old ones, and people report waiting years for needed components.

The other issue is economic: These once-$500 transmissions have gone up in price–to nearly what you’d pay for a T-56 that will bolt right to your LS1. LT1 cars also feature a different clutch and flywheel assembly, meaning more money is needed to complete the swap. The economic incentive to mate an LT1-spec T-56 transmission to an LS has simply dried up.

OPTION 2: Buy an LS1 T-56.

This method is simple: Buy the transmission you need. You’ll mostly find 1998–2002 Camaro Z28 and Trans Am transmissions listed online, and if you can snag one for less than $2000, you’ve come out on top–and since these were all O.E. units, hope that the shifter location works for you. (T-56 units for Corvettes seem to bring in less money, but don’t forget that this is a rear-mounted transaxle, not a traditional gearbox.)

You-pull-it prices look attractive but can be a bigger gamble–that is, if you can find an LS1 T-56 at all. Our local LKQ currently lists all transmissions for $135.32 plus a $30 core charge, but they don’t have anything in stock that would bolt to our LS. There’s also a tendency for yards to pull desirable parts–like the T-56–so that they can be sold at market value.

Another consideration: Rebuilds can be expensive, and there’s no surefire way to gauge a transmission’s health once it’s sitting on a seller’s garage floor. The easiest diagnosis comes from taking the donor car for a test drive, but that’s not always possible. If you’re hunting for a transmission in the junkyard, look for a car that was totaled by a collision. That’s a good sign that the car was mobile until its untimely death.

What happens if you get unlucky and end up with a T-56 that needs a rebuild? Refer back to option one, where you could wait a year for parts.

OPTION 3: Buy a brand-new Magnum.

Yes, we may be the only car magazine that’s ever done a cover shoot in the junkyard, but that doesn’t mean used parts are always the answer. Because T-56s are in such high demand, buying new might actually be the better option.

Yes, it’s more expensive. American Powertrain lists a new Magnum for $3195 plus truck freight, but that delivers a brand-new, no-excuses gearbox that’s stronger and better-shifting than the T-56 and is available in wide- or close-ratio configurations. It’s also backed by a two-year warranty. (Budget $3695 for the Magnum XL.)

We entered this exercise assuming that used would be the best option for our own project–an LS1-swapped Nissan 350Z–but after weighing all the pros and cons, we decided not to gamble on a $2000 transmission that had covered 100,000 miles and nearly that many powershifts. We spent another grand to order a brand-new Magnum. We didn’t want to do this twice.

By the Numbers

Every T-56 variant and what you need to know to plan your swap.

T-56 Transmission Guide


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Comments

View comments on the GRM forums
SVreX
SVreX MegaDork
6/12/18 6:59 p.m.

That's awesome. I needed that. 

te72
te72 Reader
6/13/18 10:29 p.m.

Good info, thanks for sharing online! I really, really hope to never need to replace the transmission in the Supra, but if that day comes, it will likely be a TR-6060 for me.

 

For what it's worth, even new, a T56 variant is cheap compared to the other 6-speed manuals that can handle the power like they can. For reference, try looking up what a Getrag V160/161 goes for these days.

yupididit
yupididit SuperDork
6/14/18 7:02 a.m.

The getrag 420g and Nissans cd009 6 speeds behind the vq35de (the one behind the vq35hr engines have a concentric slave cylinder) are also options. Both can take good amount of power and easily found everywhere. Usually cheap compared to t56 and way way way cheaper than the v160/161.

Matt_Corrie
Matt_Corrie New Reader
6/14/18 7:07 a.m.

i bought my car with the T-56 already installed - now i cant wait to crawl under it and see what i have - articles like this are like Christmas morning for me !! LOL!!

te72
te72 Reader
6/15/18 1:25 a.m.

In reply to yupididit :

I know of at least one 420g swap going on in a Supra, it's been a work in progress from what I can remember. The CD009 is indeed a good alternative, especially for those on a budget. However, identifying them seems to have been an issue in some cases. If I recall, not all of them are tagged in such a way that can confirm them as the CD009. There was some issue with a VERY similar transmission used in the Z33 that was significantly weaker, but looked essentially the same. About the only way to tell that they were not the same was when your new 6-speed decided it didn't like torque as much as you were hoping.

 

Details are a bit fuzzy in my head though, so I certainly wouldn't take my words as gospel here. I never had any intention of running a CD009, so I was skimming through the information when it popped up.

yupididit
yupididit SuperDork
6/15/18 3:24 p.m.

In reply to te72 :

You're right some of them arent labled well. But, I believe you can still buy them brand new for a very decent pricel. Like $1600 for a brand new CD009. The latest revision number is CD00A, which is identical to the CD009 just to be clear.

te72
te72 Reader
6/16/18 1:37 a.m.

In reply to yupididit :

Can't beat that price with a stick for the performance level. Unless you were under some severe budget restriction (which, why are you swapping a 6-speed in if that's the case?), I don't understand why you wouldn't just buy new. This, coming from a guy who still picks up pennies that he finds.

JBasham
JBasham HalfDork
6/18/18 10:54 a.m.

I've never driven one.  How's it shift, compared to say a T5?

te72
te72 Reader
6/19/18 12:42 a.m.

In reply to JBasham :

Can't say I've driven a T5, but a T56 is easily one of the better transmissions I've driven. It's direct, a bit notchy (I mean that in a good way), and takes a bit of a firm hand to select your gear, but... it inspires confidence that you can slam gears quickly and it will work.

 

My manual experience, off the top of my head:

-whatever is behind a KA24E in a Nissan 240SX

-whatever is behind the VG30DET in the Z31

-Toyota T50

-Toyota W58

-Toyota R154

-Miata transmissions

-Various trucks

I'd say the only one that compares for shift quality is the W58 in my experience, but those are comparatively made of glass... You owe it to yourself to test something out with a T56. Fortunately, they're all over the place. =)

JBasham
JBasham HalfDork
6/19/18 8:36 a.m.

Thanks.

I'm using T5s at the moment, but three problems.

Shifting quality is only "pretty good."

5th gear is utterly useless on the track, even on a downhill front straight.

Torque handling is okay for now, but possibly not okay where I'm headed.

OTOH, it's really light.

And there are a lot of really good rebuild videos out for it.

weedburner
weedburner Reader
6/19/18 10:00 a.m.
JBasham said:

Thanks.

I'm using T5s at the moment, but three problems.

Shifting quality is only "pretty good."

5th gear is utterly useless on the track, even on a downhill front straight.

Torque handling is okay for now, but possibly not okay where I'm headed.

OTOH, it's really light.

And there are a lot of really good rebuild videos out for it.

There is another way to get more power thru any transmission including the T5- add a device to control the hit of the clutch!

Adding the ability to control the hit of the clutch makes it possible to significantly reduce the impact of inertia on the gearset/case. At the same time controlling the hit of the clutch actually makes the car quicker by increasing the amount of power that the engine is able to produce. You can also increase the overall amount of torque that you can put thru the transmission on the shifts.

Some claim to be successful at modulating the clutch with their foot, but even with a lot of trial/error practice consistency will be lacking. It's much easier to precisely add a bit of slip time by using a mechanical device, here's a list/links to devices specifically designed to do the job for you...

Tilton Flow Control Valve
ClutchMasters Flow Control Valve
Magnus Launch Control Device
ClutchTamer Clutch Slip Controller

The last one on the list is my personal favorite as I designed it myself, but it's also the only one on the list that works with mechanical clutch linkage as well as hydraulic. Anyone who has witnessed an NMRA Coyote Stock race in the last couple years has seen the ClutchTamer in action.

If at some point you were to decide to upgrade from a T5 to a TKO or T56, that same device will improve their power handling capabilities as well.

Grant

wspohn
wspohn Dork
6/19/18 7:39 p.m.

Understand why you might want a CDV (clutch delay valve) but I hate them.  BMW owners learn to drive so they can remove the valve.  Plus by introducing slip on engagement, they may be easier on drive line but are harder on clutches.

weedburner
weedburner Reader
6/20/18 9:18 a.m.

I don't like CDV's either, as they slow down the entire release cycle of the clutch pedal which screws up the shifts.

The ClutchTamer is selective, as it only slows down the last bit of pedal travel that affects how hard the clutch hits the drivetrain/tires. The driver still has full control over the part of clutch pedal travel that affects speed/quality of the shifts. The net effect on clutch component wear is not what you might think. It basically converts the clutch slip part of the pedal release cycle from hi clamp/short duration to less clamp/longer duration. Less clamp/longer duration slipping creates a much lower torque spike to be passed along to the rest of the drivetrain, but net wear/tear on the clutch components themselves ends up about the same.

 

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