Which 944 transaxles are class legal? Here is a link to the codes:

www.clarks-garage.com/shop-manual/trans-04.htm

Eric

Excerpt from the rules helps in figuring out, in general, what year parts are eligible:

4 Eligible Models
1983-1988 Porsche 944, Normally Aspirated, 2479 cc, eight valve engine 1987-1988 Porsche 924S, 2479 cc, eight valve engine

4.1 Chassis Swaps
A 944-SPEC may utilize any year chassis in the above eligible models as well as the 1987-1988 944S and 1989 944. No other 944 or 924 type chassis may be used to build up a 944-SPEC. In all cases body work, engine, transmission, engine electrical and suspension components must conform to the list of eligible models and to the modifications expressly listed in these rules.

The transmission section then clarifies gear ratios, etc. that can be used:

14.2 Differential
The stock 3.889 (9:35) final drive ratio must be used. Differentials are free.

14.3 Transmission
First through fourth gears must remain stock for the Porsche 1983-1988 944 naturally aspirated and 924S models. Updating to the stock shorter fifth gear from the 924S and the 1988 944 is allowed.

The allowed gear ratios (gear tooth count) are:
First 3.6000 (10:36)
Second 2.1250 (16:34)
Third 1.4583 (24:35)
Fourth 1.0714 (28:30)
Fifth 0.7297 (37:27) or 0.8286 (35:29)

Ensuring the gear ratios are all correct and match what is expressly legal is the important part. Sometimes gear stacks get swapped out so it is not 100% reliable to go on the stamping code on the bell housing, although usually the only gear that doesn't match is the 5th gear, since it is the easiest to swap and done regularly for fuel economy or performance.

So, any "case" (from any model) is okay as long as the innards conform, i.e. the correct gear ratios and with or without LSD?

In all cases body work, engine, transmission, engine electrical and suspension components must conform to the list of eligible models and to the modifications expressly listed in these rules.

Thanks--I believe I understand.

So basically, if it came in a 944 in north america with a 2.5 it's legal. The one you want is in the late cars or 924S with the limited slip and short 5th. Like Jason said though lots of swapping has gone on so going by case number doesn't help a ton unless it's original to that car. For instance the current trans in my car has a factory LSD and short 5th, neither native to that case.

Now you could cheat and get the trans from the Audi 5000 I think(maybe also the 4000) of the same vintage and swap out the gears. The final drive is shorter and I think some of the ratios as well. Not sure that it would do any good however but those cars do come with a limited slip quite often, especially back east.