Samdog

I tried a search first but couldn't find anything.

I have an 86 944 track car and a later transmission that has the lower (numerically higher) 5th gear. I want to swap that gear into my trans. Does anyone know of a write up on how to do this. I've heard it is a pretty easy swap.

Thanks!

Samdog

Porsche-O-Phile

To my knowledge it is impossible to do anything on the transmissions without very specialized presses and equipment. I haven't looked into it any further than that though - as soon as I heard this I automatically figured "shop labor rates of $100 an hour = forget it". I haven't bothered looking into it beyond that.

Oddjob

I dont recall ever coming across a post on doing this.

Swapping the 5th gear set isnt too bad, and can be done with a pretty standard gear puller. But I would definitely recommend using the factory manual as a reference. Ive opened up and worked on a couple transmissions, but would not attempt to give you any instructions myself (w/o reading straight from the manual). See if you can borrow the transmission section from someone or find someone to send you a copy.

M758

check over in the NASA forums.

http://nasaforums.com a few 944 spec racers have done this and I have heard it can be done with the tranny in the car.

You can also just swap transmissions. I have done that on my 944. My 84 has a 87 924S transmission complete it in it.

Porsche-O-Phile

Well, this has the potential to be a pretty useful thread. . .

Instead of swapping transmissions, the reason I'd considered it was for the Callaway car. I wanted to see if there was a way to take the hardened 1st and 2nd gear and stronger R&P setup out of a 951 transmission and transplant it into an n/a transmission to retain the higher upper gearing for better top-end. Alternatively one could transplant all the guts from an n/a trans into a 951 case which would be nice (you'd have the oil cooler, etc.) but a lot more work.

Or just use a 968 6-speed. . . By the time all is said and done, it might not be that much more expensive and you wouldn't have to worry about the speedo hookup on an early car.

tifosiman

P-O-P, you are getting a little off-track here. 5th gear swaps are not too bad as the pair of gears are on the end of the shafts, at the back of the trans, and can be done without a press or some of the other tools needed for an R&P swap, re-shim, etc. What you want to do is still not easy and still requires the tools and the press.

Oddjob

170 mph with a turbo trans, is not enough top end?

I am all but positive that you Cannot interchange the n/a and turbo guts. The Turbo input and pinion shafts are different than the n/a, and therefore all the gear sets do not interchange.

I think you can swap the casings, put all n/a guts in a turbo case with the oil cooler setup (I could be wrong on this), but you cant put n/a gears on the turbo pinion and input shaft. I know of an n/a that has an LSD and oil cooler from a Turbo S on it, but Im not sure if they put the n/a guts into the turbo S casing, or if they removed the oil cooler assy and LSD and installed that in the n/a case.

M758

You can swap the .83 ratio 5th gear pair from a 951 in to a 944 NA gear box to replace the .770 gearset.

I know of a few 944 spec guys that have done this.

Porsche-O-Phile

Wanted to be able to break 200. . .

Oddjob

Fair enough!

Quick check, so if its possible, the -87 944 n/a 5th (0.730) with the turbo 3.375 R/P would be good for 194 mph at 6500 rpm w/ 245/45/16 tires. Could break 200 with higher revs or taller rear tires.....

Interesting on swapping in the Turbo 5th into an n/a trans. The turbo (S, S2, T, TS) 0.829 5th gear does have a different part number than the 924S and 88 n/a 0.829 5th. I never knew they were interchangeable.

Several years ago now, I was told by a guy named Kevin Gross (who I was referred to by either Jim Pasha or George @ 944Ecology - I cant remember which), that the n/a gears were all narrower (weaker) than the turbo gear sets and can not be swapped. I was specifically asking about 3rd and 4th, so he may have just been talking about those individual gear sets. Have never looked into it since, and have never actually compared the parts side by side, since the transmissions I have worked on had Turbo gears (Turbo S and 944S).

944J

What about doing putting hardened 2nd into a na? My 2nd gear is gone, the others work fine. Would it be a lot of work to put a normal na 2nd gear in or a hardened 951 2nd gear?

tifosiman

Way cheaper just to get another used 944 N/A trans at this time. Buying the parts and having the shop do the work will cost more than a used trans, and while you have it cracked open you will want them to go thru and replace the seals, synchros, re-shim the R&P, etc. And, to do it yourself still requires the parts, the Factory Service Manual, a lot of time, and a shatload of money in tools. Unless you just want to learn and get the satisfaction of doing it yourself, have the time, and have another mode of transport, then it is worth it and a valuable experience.

kasturbo

Tifo, did you ever finish that one that you were working on?

tifosiman

Hey Kevin, everything is done except for shimming the R&P (I put an S2 R&P in it). I may add a quaife LSD before buttoning it back up, I am uncertain.

kasturbo

Thats good to hear. Did you see the quaife in the classifieds for sale? Maybe after I see yours hold up I'll hire you to rebuild one of my two busted boxes! I'm collecting like you now, I've got two good, two bad, and a spare r&p.