T56 Mods?

[Chainsaw]

I'm still trying to decide between the TKX and the T56 transmissions for my build. Leaning to the TKX, but the idea of the 6-speed wont go away. Can anyone point me to a thread that discusses the mods that need to be made to the tunnel and transmission support A-frame to accommodate the T56? If no existing thread, can anyone tell me what needs to be done to squeeze the T56 in there?
Thanks
Jack

[Rdone585]

As far as I know, you have to have an IRS rear end to run a T56. It's slightly longer than T5, TKO, or TKX and the driveshaft just doesn't fit well with a straight axel rear. To bad because I have access to a T56 but can't use it in my car. So, if you're planning an IRS build, then a T56 is a good choice.

[edwardb]

IRS only as already mentioned. Note I've seen some builds where they moved the motor mounts forward to overcome this limitation. But that brings in lots of other issues, including header/side pipe alignment. Assume you're not going there... Most common areas cited are the e-brake and the transmission mounting frame. Talked about in this thread: https://thefactoryfiveforum.com/showthread.php?7998-T56-transmission-question. Note for a Coyote you have roughly an additional 3/4 - 1" of room forward (it's shorter than a SBF) but don't know if that's your build plan. IRS only is still the consideration.

FWIW, I have a T56 in my Gen 3 Coupe. Fits easily. After having TKO's in my previous Roadster builds, I like it a lot. It shifts great and I don't mind the extra gear. But the major knock on the TKO has mainly been how it shifts and this was addressed on the TKX. I don't think you'd be unhappy with it. Also the T56 has an additional "complication" with a solenoid on the reverse gear. It's a nice feature, e.g. locking out the reverse gear gate except with the solenoid is energized. But it's something you have to address during your build. Several ways to deal with it.

[Jim1855]

The T56 is longer by a few inches and heavier by about 30#. Larger in diameter at the front and maybe $1k more expensive.
If you're happy with 5-speeds and can select the OD ratio that you like on the first pass then the new TKX simplifies things and shifting is supposed to be excellent, similar to the T56. I have a TKO-600 with the .6x OD and like the ration.
But if you want the two OD ratios, don't mind the length, weight and price the T56 is, what I think, an excellent choice.
Driveshafts - the T56 will be real short, maybe 2-4" between the U-joints where the TKO/TKX will be 6+ inches long.
The Tremec website has the specs.
Jim

[Blue Viking]

Not on the road yet, but T56 installed with a stroked 302, mk 4 roadster Had to cut a piece of the A-frame transmission mount for clearance. Removed parking brake brackets from frame and moved one piece of frame a bit in same area due to interference. Shortened driveshaft a lot. Think approx 1 inch tube, could probably have been 2 inches. Swapped IRS pinion flange with shorter truck flange, and also swapped pinion end yoke on driveshaft to eliminate adapter. Installed Levy lowering motor mounts, which in addition to on spacer in the rear gave me perfectly parallel engine and IRS centerlines, working angle is 2. Note, not sure if I would have had to remove the parking brake brackets and move one square tube if I had installed the lowering motor mounts first, did that afterwards.

[Hoooper]

I have a close ratio TR-6060 AKA t56 magnum. I just ditched the A-frame and made my own rear mount, but the mounting location on the tr-6060 is different from the t56 magnum so probably not relevant. No mods needed to the transmission tunnel and I have my engine back about as far as you can go and still get all of the needed yokes together on the driveshaft, the actual round shaft part of my driveshaft is only about 1.5" long. The 0.50 6th gear is real nice for cruising 75+ on the freeway, doing that at 0.74 ratio 5th gear really wears on you a lot more, but given the TKX improvements over the TKO thats really the only benefit I see for this application.

[Chainsaw]

Thanks to all. Great info. I have ordered the IRS option and have diff sitting in the garage already. I intend to use a SBF, so I’ll have to deal with the length of the set-up. Still considering the T56, but if someone starts selling a true mid-shift kit for the TKX by the time I order my drivetrain, I’ll likely go that way. The T56 itch hasn’t gone away, however.

Does FFR or someone sell the correct drive shaft or is this something I’ll have to get modified locally?

[efnfast]

Use an alloy T5 instead of the TKX - it's lighter by 50lbs, a true mid-shift and can handle 600+Tq. Levy Racing built mine back in 2005 and it's been rock solid after putting massive torque through it for over 15yrs

[ChasNMe]

wondering if you (chainsaw) found out exactly what needs to be modified for the transmission support or where to get a correct length driveshaft (or who might be able to shorten it). I am leaning towards the T56 also with either a BPE 347 or Forte's 363. or if anyone else had a detailed answer or pics of the modifications it would be much appreciated. thanks, jake

[Chainsaw]

Never got a specific answer on what needs to be done to the a-frame other than what’s in this thread. I’ve not pursued the drive shaft question. I intend to order the engine/transmission set up next week from Mike Forte, so I’ll pick his brain then if I decide to go with the T56.