Tremec T-56 Viper Spec Transmission fitment

[Carlos C]

Has anyone tried to fit one of these transmissions on the Roadster?

Years ago, I installed the Viper tranny on my '88 donor. At the time, it was the only manual street tranny that could handle the 700+ lb/ft of torque my 351W puts out. I want to use this powertrain on the kit. Although the kit is almost 1000 lbs lighter than my Mustang, Tremec advised me that the TKO may not be able to handle that much torque, even on a lighter vehicle. This is a $3K tranny, so I definitely want to put it to good use.

My concern is that this tranny is considerably longer (up to 6") than the the other offerings, which could make my driveshaft too short. I know that it would work if I use the independent suspension, due to the fact that the pumpkin is stationary, but I will be using the 4-link racing set-up from my donor. Although my rear suspension is completely adjustable, and can set the differential further back to help offset the extra tranny length, I may run into clearance issues with the fenders.

Help...

Carlos

[2FAST4U]

You can't run the T56 with the 4-link. Only with the IRS

[GMG2]

I have the shortest of the T56s (CTS-V) behind a 351w going to IRS.

I made custom mounts to move the engine forward a little (careful on that - you'll need custom headers if you go far). It had to move forward a little or the bellhousing was in the diagonals.

Made a custom output flange so the driveshaft could be as long as possible (CTS-V uses a flange / guibo, the guibo won't fit without modifying the 4" cross tube).

My driveshaft ended up 10.5" u-joint to u-joint. I wouldn't try anything but IRS.

If you want it in there straight (I did), you'll also need to move the bar that the handbrake mount is on.

Good luck,

Mike

23544

[GMG2]

The mid-shift kit that fits in the plate above the skip-shift solenoid comes up in the middle of the transmission tunnel nicely (no bars have to move there).

That's all on a Mk4.


Mike

[Carlos C]

The mid-shift kit that fits in the plate above the skip-shift solenoid comes up in the middle of the transmission tunnel nicely (no bars have to move there).

That's all on a Mk4.


Mike

Mike:

I'm not really concerned with the position of the shifter, and I know that's an advantage on those transmissions. Unfortunately, the problem for me lies in the total length of the tranny's case.

My dilemma is that I could use the T-56 when I build the Hot Rod, but it'd be overkill for the engine I plan to use, and I cannot use this supercharged 351 on the Hot Rod, because the blower won't fit within the engine compartment. So, I guess I'm stuck using the TKO with the 351 on the MK4, and will have to cross my fingers, while hoping that the 1000-pound difference between the Mustang and the MK4 will prevent the TKO from exploding from 700 hp and 700+ lb/ft of torque.

If anyone else has any other ideas, I will welcome them. Thanks to all who have responded.

Carlos

[michael everson]

Just my opinion, but 700/700 is ridiculous in a 2200 pound car. Your just going to fry tires and have a nearly urn drivable car. Some of the best roadster I've have built and driven are with stock drive trains
Mike

[Carlos C]

Just my opinion, but 700/700 is ridiculous in a 2200 pound car. Your just going to fry tires and have a nearly urn drivable car. Some of the best roadster I've have built and driven are with stock drive trains
Mike

Mike:

Believe it or not, I drove this car on the streets almost on a daily basis; and as long as I kept the boost gauge needle on the vacuum side (which was easy to do), the car was very tame and friendly. I guess that another option would be to take off the blower and just use the engine naturally aspirated. The problem with it is that I built this engine specifically for a blower (compression, cam, intake, injectors, etc). Out of pure curiosity, I tuned and dyno'ed the engine prior to adding the blower, and only made 335 hp, and was not very fuel-efficient. It woke up immensely once I added 12 psi of air and tuned it for the blower.

Either way, my plan for the '33 is to make it a comfortable daily driver; so putting a very powerful engine on it, would defeat the purpose. The T-56 will be too much more than what I need for that build, while the TKO would not be enough on the MK4. I could always un-install the blower on the 351 for the MK4, but that means that I'd have to purchase smaller injectors, re-calibrate the mass-air sensor, re-tune the engine/computer chip; not to mention that all the money I spent to get this engine to handle that much power (and not destroy itself in the process), would go to waste. I could try to sell the engine with the blower and the tranny, but I will never get anything close to what I spent for them.

Carlos

[Avalanche325]

If you did go IRS that would probably explode the first time you stepped on it.
I would think that only way to use that transmission is to move the engine forward. There is a ton of room forward of the engine. You would need custom headers and welding would be required. Save up all your spare change for tires.

[Carlos C]

If you did go IRS that would probably explode the first time you stepped on it.
I would think that only way to use that transmission is to move the engine forward. There is a ton of room forward of the engine. You would need custom headers and welding would be required. Save up all your spare change for tires.

I spoke with Jason at FFR about that same idea, but he said that moving the engine forward enough in order to get the minimum length on the driveshaft, would put the oil pan where the front cross member is.

At this point, I'm thinking that I should use the TKO instead. I just don't feel like re-inventing wheel (or in this case, the frame), just so I can use that the T-56.

Carlos

[Carlos C]

Well, I found a way to have my cake and eat it too. i just ordered the Coupe. The T56 will fit, using the 4-link, with minor modification to the transmission mount. The Coupe is also better suited for the power plant I'll be using. It's not the kit I originally wanted to build, but I'm still excited to start this project.

[ponyboy1965]

Could I run a T-56 with 3-link?

[Carlos C]

As discussed on the previous posts, the T-56 will fit on the Hot Rod, on the Coupe with slight modification to the tranny mount, and on the Roadster, but only if using the IRS.

Carlos

[ponyboy1965]

Thanks.... Do you like the 3.73 gears?

[Carlos C]

Love them. They really wake up the car. The bonus effect when using them with the T-56, is that on 6th gear at 60MPH, you'd be running close to the same RPM as with a stock Mustang on 5th and carrying 2.93 or 3.07.

Carlos