kasturbo

No the S2 and S are differant. The S2 is the stronger of the two. The S2 is the same as the turbo, but with a differant final drive. Look at Danno's gearing chart and you will see the differances in the final drives.

Kokopelli

My '86 944 n/a has a transmission from an '89 car. How can I tell if it's from a 2.7 or an S2.

Fishey

All 944 trannys suck...

Look for the 924 tranny that is made by porsche-getreg (has a diffrent shift pattern).

xsboost90

the 2.7 has the same trans as the n/a 2.5 i believe, i had one, didnt feel different.

kennycoulter

okay my dad makes guns, and i only read the first page. i am kenny. anyway. how about if you buy a regular used tranny, take it apart and heat treat the ring and pinion to a higher degree. i can call my dad to get the color heat coding range thingers.......or was the turbo trans beefed with something like a different alloy? well anyway its just an idea. also, the shims SHOULD be the same if the part wasnt changed any right?

Scott at Team Harco

You had me lost there for a minute - but I finally caught up to you after a couple of re-reads.

In regard to the last question about the shims.
a) You make the assumption that the preload and gear mesh was correct when the transmission grenaded. Think about that for a minute....

If everything WAS right, I rather doubt we'd be having this thread.

b) Each ring & pinion set should be specifically matched to each other. They are not necessarily identical to all others. There is in fact, a ring and pinion set that has a slight size differential (no pun intended) than the standard part. It has an identifying mark to let the technician know what he is dealing with. I don't recall the details, but it's something along the lines of an oversize or undersize (I haven't looked in the manual lately).

c) What if the bearings need replacement? What if the bearings, races, housing, etc. have all recieved years (miles) of use and abuse? These things are not wear-proof. Tolerances become larger. Things get loose. (see item "a" above)

d) If you are going to all the bother of taking this thing apart and rebuilding it - you want to get it as close to spec as possible. That means you must verify gear mesh and bearing preload. If not - you're going to be doing this again in the very near future.

In regard to heat treat:
Gears are extremely complicated mechanisms at the microstructure level. Volumes of text books are written on the forces and reactions involved. The teeth on gears are designed to have the forces concentrated on a very
specific "pad" of each tooth face. Deviation from this causes extreme stresses and eventually a fracture will start. The proper heat treatment to make these gears as strong as possible - yet not brittle - has already been taken into consideration. It is highly unlikely a gunsmith (for example) is going to do a better job of heat treatment than the manufacturer of the gears. (no offense to your father, by the way).

Unfortunately, this is not as simple as it may seem. It's not rocket science - but it's not far off.

tifosiman

This is all good stuff. I am learning a lot. All I really knew about the tranny was the theory on how it worked, but not how to work on it.

I just bought Andy's spare trans that we installed Sunday. It wasn't my first choice, as it has 32K miles more on it than my car, but Andy needed the money and changed my plans a little bit. But, I still have my old one now. And, there is at leasst a working trans in the car. Whether or not I do the last few autocrosses of the season is up in the air at the moment.

I think what I am going to do is take the old one fully apart and inspect. Provided that the gears in the trans are fine, I am going to attempt a rebuild over time. I'll buy a new R&P, an LSD, shims, etc. slowly in increments, and then once I have the parts I will start the build process. If the gears are toast as well, then I'll button it back up and save it as a core in case I find a dismantler that has an S2 trans (with LSD maybe).

I haven't heard an answer to this question yet (or maybe I missed it), so I'll ask again: Does anyone know if the r&p from an S2 or a 951 will fit in my trans with my gears? If so, that would be the one to buy instead of the weaker (I'm assuming) n/a unit.

Thanks again for all of the input.

Jeremy

adie

I retro fitted the same idea, I have an N/A r&p in a late 944 turbo box, I needed the higher gearing for accelleration. I have the turbo r&p fitted back on the N/A box just in case, also the turbo was an LSD unit, and hte N/A an open diff, compleatly interchangeable in my expierience.

Fishey

What tranny you runnin in the 10second car? a drop of some sort?

tifosiman

How would you rate the difficulty level of the work to do that? Thanks!

Fishey--------------I think he has the turbo trans in his car, from the sound of it.

kasturbo

You can do it, but again this will change your final drive making the cars power band all off. The gearing is the same in each box, but the final drive is what they changed. They beefed it up in the turbo and s2 boxed. If you found a s2 ring and pinion you would be set.

tifosiman

Right on. So now I just need to source (when I have some cash) an S2 r&p and an LSD. This should be a fun little project..........

I would have to think that it would be cheaper, and probably easier, for me to rebuild my old trans (provided that the rest of it isn't trashed) with the S2 r&p and a new LSD than trying to find a fairly rare S2 trans with LSD for sale.

Carrera51

I think Fishey is right. The 5 spds from the early 924 (made by Porsche) are supposedly stronger than the 944 box. They have the 928 shift pattern. I saw a 924 at Summit Point with this trans. I think it was an 80 or 81.

adie

It's a turbo with the cooler, LSD and the n/a gearing (actually remade by a firm who cuts gears for rally cars), for you it's doable, for majority of people who need help in choosing the correct polish it may be beyond them. I had to make a rear seal as I punched the rear one out, this took some time to remake. the rebuild of the box was quite straightforward, I recut the main bearings so I could set up preload and be able to put the new race's back in. I also recomend going to a bearing suppliers as the numbers are on the side and about 1/10th the price from P/dealer, I have the numbers if you don't want to get your hands dirty (I brought 2 sets, 1st from Porsche and out of interest I poped along to my local bearing supplier, at as they were identical and so cheap I got a spare set). I truly don't think you'll have a problem with it. I never had a manual (haynes or workshop) when I did mine, I also don't expect mine to last long, however everyone said it wouldn't even get me through the first season and 6 seasons later it's still going strong.

Scott at Team Harco

Adie,

Do you race your car at the Grand Bend Motorplex? I'd like to see you run sometime. We vacation at Pinery Provincial Park every so often.

Let me know if you do and what dates. Thanks.