Thread: Tremec

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There seems to be a lot of confusion about Tremec Transmissions, so I thought I would offer a few insights that I learned as I was shopping a couple of years back. You can find the history of Tremec, and all of the different technologies that have come together under one corporate JV, but the bottom line here is that Tremec has two distinct and totally separate product lines. First is their OEM/Corporate line, which produces application specific transmissions for OEM suppliers, generally with reduced torque capacities and less expensive components to keep costs down on a unit price basis (read this "to keep the corporate accountants happy" ). Second is their Aftermarket/Performance product line, which is where you get the good stuff . Evidence of the two distinct lines is clearly shown on Tremec's Home Page - Tremec While a transmission may carry the same general "family" designation, the products in the two lines are drastically different as can be seen in the full product part number where the design torque capacity is clearly denoted. A large aftermarket industry has developed to "toughen" OEM Tremec products which were originally designed for the output of a specific OEM model vehicle. This "toughening" process can be quite expensive.

If a person takes time to investigate the Tremec Aftermarket/Performance line they quickly see the difference. While the gear ratios may be identical to an OEM application the torque capacities are not. The Ford T5 was used in a ton of applications, and is a Tremec transmission. It is a very good transmission, but if it is used hard has a track record of shelling out in some pretty spectacular explosions - the term "grenade waiting to explode" has been applied to used T5's. If you don't know what it's seen, then you don't know how reliable it is going to be. To add to the confusion there are several OEM applications of the Tremec T56 out there with lower design torque values, but the T56Magnum from Tremec is a 700ftlb monster, and their TKO500 and TKO600 are good for 500ftlbs and 600ftlbs respectively. This does not mean that there is not a stronger tranny out there, but we need to be clear about your source. If you're looking to buy a junk yard OEM unit then you need to research the full part number to discern the torque capacity that was designed in for the original application.

This is that age old problem. Do I buy the Aftermarket/Performance tranny up front, and shell out the bucks to get it, or do I buy the OEM version from the junk yard? If I buy the OEM version do I take a chance and drive it "as is", or do I spend $2000 having it rebuilt and "toughened". What we tend to see is a person stepping over a dollar to pick up a dime, buying the OEM expecting Aftermarket performance, and then complaining about Tremec when it breaks. Most of us probably don't actually need the torque monsters, but they sure do provide some peace of mind if you can justify the costs. Just my $0.02 on Tremec's. I love my TKO500, which was built for Aftermarket

Thanks for the write up. This is something I'm thinking about.

I actually spent some time this past weekend hunting around for info on suitable manual transmissions for a '32 roadster with a SBC, and where I might find sources and prices for planning purposes. I have a gut feeling I'd be happier with a manual vs the TH350 in mine now but since I just got it I'll drive it for a while to see if it turns out that way.

So your TKO500 is a 5 speed and I was wondering if there is any advantage to a 6 speed tranny. I guess with 6 the ratios are closer but I'm not sure that's really needed in a sub 2400 lb. hot rod that's not going roadracing. And then of course there's the clutch...it should hold all the power/torque plus some safety margin but I wouldn't want an overly stiff pedal effort. To get a reasonable pedal effort, does it have to be a multi-plate clutch? I run a triple disc clutch in my other car (6 sp) and it holds tons of power, but I'm not yet familiar with the trans/clutch combos suitable for my roadster.

Good write-up RSpears! Definately some words of wisdon and thanks for sharing your experience.

Nick,
I got my TKO 600 as a complete package from Mike at Forte's Parts Connection Forte's Parts Connection - TREMEC, FACTORY FIVE COBRA PARTS, FORD RACING PARTS, FFR, MUSTANG, TRANSMISSIONS, T-56, T-5, TKO, TR-3550 After hearing about him here on CHR I sent him a message, we talked about what fit my build, and I ended up buying a complete package from him - Tremec cast bellhousing w/dowels, flywheel, clutch, hydraulic slave, and starter along with the tranny. My clutch is a Valeo single disc, I've never had a problem with it holding the torque and the pedal pressure is low - no difficulty actuating it at all. The Valeo Valeo Clutches » Products » Clutch Kits » Performance Clutch Kits :: Performance Clutches :: Valeo Clutches is used a lot in the Cobra packages, including their race applications, and you'll see lots of discussion about them in the Mustang forums, too.

On the 5spd vs 6spd, the big difference in my mind is that the 6spd gives you two overdrive gears, on top of kicking you up to 700ftlbs of torque capacity. You have two different gear ratio selections to choose from, one with 5th at 0.74 and 6th at 0.50; or with 5th at 0.80 and 6th at 0.63. The selection of your transmission needs to account for all of the variables - your engine torque curve (rpm where you're well up on your curve is critical), rear gears and tire diameter all interact for a good selection. I can tell you from my experience my 0.64 final drive puts me just below 2000rpm at 70mph, and the 0.50 would drop me down to 1560rpm which is a bit low for me. If I were running a T56 6spd I'd be on 4.56 rear gears, or even another notch lower which just doesn't make sense for an around town/cruise car in my mind.

If you get ready to jump into a stick and decide to go with a new tranny vs salvage I'd advise you give Mike Forte a call, explain what you've got to him (engine, approximate HP & torque, rear gear ratio, rear tire diameter), and let him chew on it for a few minutes to come up with a recommendation. You will not be disappointed with Mike - he's a great guy, and he still remembers me (Roger from the KC area) any time I call him.

Roger that, man. Thanks a bunch. I'll give all your facts and advice serious consideration.

Prior to buying my '32 I checked out and drove a Speedstar '33 and it had a Corvette 6 speed. Besides the styling of that one not being to my taste, I liked the 6 speed part of it.

The T-56 is a very large transmission! You may want to do some measuring in your Deuce, 3 pedals and the bulk of the T-56 could make having adequate foot room a real challenge!

Originally Posted by Dave Severson

The T-56 is a very large transmission! You may want to do some measuring in your Deuce, 3 pedals and the bulk of the T-56 could make having adequate foot room a real challenge!

That's very true, Dave. I fought with my TKO600 and the original tunnel for quite a while before I finally just cut the tunnel out and molded in a new one, and the TKO is significantly smaller than the T-56.