I'm looking at a t56 out of a 2006 ctsv and was wondering if anyone had any insight on any potential problems or differences if any. Or is it identical to the t56 that comes in a gto camaro etc. Thanks in advance for your imput.

 

Very hard to make that one work, and the gear ratios are not optimal.

You'll need a custom trans mount and driveshaft.

 

the gto, cts-v and the c5 z06 are the same for the most part the only difference is how the shifter is mounted out of all 3 you want the gto and the fbody t56 is different as far as gear ratios and its not as well built as the gto but if you do use an fbody tranny you have to use a gto style shifter it will put you right in the factory location if you go by how Howard did the swap

 

No those 3 transmissions are not the same. They only share the same gear ratios and internal specs (mn12). The c5 Z06 box is a transaxle- not gonna work in the RX7. The CTSV box has a remote mounted shifter and a output flange, not a slip yoke - the shifter will be at the armrest and have fun installing your driveshaft with that.

The GTO is a viable option and has a couple upgrades over the Fbody T56, but the ratios suck for a light RX7 with a V8. You'll be shifting all the time. An Fbody trans is good condition or rebuilt is what you want if you can find one.

The close ratio Magnum T56 is ideal, it has the Fbody 1-4 and the GTO 5-6 gears. But you'll need to modify the shifter, the shifter hole in the tunnel, the mount crossmember and your driveshaft slip yoke.

I may go the most expensive option, a Magnum converted Fbody trans. You just need to change your slip yoke, and it has the close ratio gearing with all the Magnum upgrades.

 

thats why i said you got to use the gto tranny out if the 3 if your going that way but yeah your spot on

 

The gears in the GTO/MN12 T56 suck for a lightweight car, they are too short and you'll be shifting all the time, wasting the broad powerband of your V8. The GTO trans has SHORTER gears, and the gaps between them are wider (except for first) in the first 4 gears.

The GTO 5th and 6th gears are nice for a track or aggressive street car.


F-body T56 ratios are 2.66/1.77/1.30/1.00/.74/.50.
The GTO T56 has a 2.97/2.07/1.43/1.00/.84/.63

The close ratio T56 magnum is the best choice if you are building your car from scratch. It has the F body 1-4 and the GTO 5 and 6 gears.

 

Define what you mean by longer? The 2nd gear of the Fbody box is actually a useable gear. 2nd gear in the GTO box is too short. You almost need to shift twice to get to 60 which is dumb in a car with this power to weight.

Both T56 versions really need a taller rear gear. I have 3.73s in my and it is about perfect with the Fbody. It would be less than optimal with the GTO box. Having to shift into 4th to get above 90 sucks.

 

I am a Tremec retailer and sell the T56 Magnum for all kinds of swaps.
As LargeOrangeFont said..... it truly has the best ratios.... and 5th gear is .80 so you stay in your powerband the entire time. Basically a close ratio 5spd with .63 6th gear overdrive.

I'm pushing around 1400hp thru a stock T56 Magnum and shift mine at 7800rpm without issues. There is a 2JZ guy making more power than me and he shifts his at close to 10K RPM! They are stout.

The GTO gearing and most TR6060 production transmissions don't have optimal gearing.

 

I am currently running a CST-V engine and transmission in my FD. I don't think it is that hard to get things to work. I made an aluminum upper plate to mount the shifter base to. I shortened the remote shift linkage about 7 inches. Everything sits in the center console perfectly. Either way you will need to make a driveshaft for the swap, I required a adapter flange from DSS with my swap.

I have been using this current setup for 3 years without a single problem. I would agree on the short gears in the transmission. I am running a 4.10 rear end and will be looking to go to a 8.8 with a 3.73 or 3.55 ratio. My top speed at Road America is low and I am shifting a lot.

If you can cut and weld you can make this transmission work.