N/A and TT transmission difference?

[eldewen]

I'm in line to buy another automatic transmission for my 93 N/A, but I just realized it's a TT transmission. Is there any difference between the two?

[tmorgan4]

I believe the starter area is slightly different since it must space the starter further out due to the larger TT flywheel. Not that the starter couldn't be made to work....

Aside from that I'm not sure what other differences exist.

[thoroughbred3.0]

i believe the manual trannies are the same, but the autos are not...

[LIBRILZ]

The N/A transmission also has closer gear ratio's for better acceleration due to the lack of no twin turbos.

[Nicksemianiw]

^^^^I don't think so, I was under the idea that it was only the gearing of the rear end that did that.

[supermario680]

correct, only the rear end is geared different, the transmission gears are the same but the bell housing is different for the TT's larger flywheel and the starter needs to be shimmed out to make up for the bigger flywheel.

[eldewen]

So I just pulled the NA auto out today (already had ordered the TT trans so I have it) and side-by-side, the turbo transmission is about an inch longer. The bolt patterns in the bellhousing are the same (FSM shows different bolt lengths, though) but as someone said, the flywheel is different - the torque converter bolts are about 6.5 inches apart on the NA and 7 on the TT. Also, the propeller shaft yoke is much bigger in the TT and I'm assuming since it is a longer trans that a different shaft will be needed.The biggest problem I saw is that the transmission crossmember (wasn't included in my TT trans, just going off mounting holes on trans) sits about an inch further back, so none of the crossmember holes will line up.

Has anybody done this transmission swap? I may be overlooking something, but it looks like you'd have to drill/thread new holes to get the crossmember on, which is definitely not worthwhile.

I got a TT trans because it was much cheaper and plentiful (from coming off auto TT clips) than the NA trans (not to get a beefier transmission) and at the time, I couldn't find info saying they're different.