[demitristewart]

i've got a 72 ford mustang grande that i pulled the transmission out of (needs a rebuild). thought it was a C4 but it's actually an FXM.

can anyone tell me the real difference between these two transmissions? which is better and why?

also;

i'm trying to figure out the gearing in the rear end. anyone know what was stock for these rear end when these cars came out (it's a posi, just can't figure out what the gears are)?

thanks in advance!

[farna]

The FMX is actually a Borg Warner/Studebaker/Ford joint venture. Ford made their own version of the trans the team developed. Most rotating parts are the same, but Ford made their own cases and valve bodies. The rebuild kits cover all models, just threw in different valve body parts and pan gaskets.

It's hard to find things like shift kits for the FMX. The C-4 came later, but I think there was some overlap where the FMX was used along with the C-4. you will be able to find speed/build-up parts for the C-4, but not likely for the FMX. I don't think the FMX was used behind anything bigger than a 302, and not in the full size cars. It's a medium duty trans at best, fine for cruising, but not a good racing or heavy towing trans. C-4 isn't either in stock form, but as I said -- you can find build-up parts to strengthen the C-4.