Disassembling a 5 speed Transmission (Pic.)
 

Well I installed my replacement tranny this week and it works great - shifts without any crunch and doesn't make any noises. My old tranny had a loud tapping noise, louder when warm that was related to speed - sounded like someone was back there with a ball pein hammer!

Anyway I am disassembling the old one to see what the problem was. I took off the RH side cover expecting to see a tooth missing on the ring and pinion, but they look OK. theres a ton of stuff on the magnet though and the stub shaft bearing is worn and pitted.

My question is how to proceed from here to disassemble. I tried to remove the rear most chunk and it has begun to come off by about a sixteenth of an inch but doesn't want to move any further. Does this piece just need to be pulled off more forcefully or do you first split the thing at the next joint towards the front? Anyone with any experience in this area?http://forums.pelicanparts.com/uploa...1208629200.jpg

I take it you have removed the shift linkage?
Seperate at largest flange first will take some force due to the dowells top and bottem.
Then lever out rear round plastic seal at the very rear, you will see a large nut, this needs to be undone and all will become clear.

Put it back together and give it a good blast with the power washer.

That would help the most. You might be asble to see something that is covered in goop.

You will need to start where you say "Try There" first. I think you need to remove the selector part first. You remove the bolts first and then try to separate the gear case from the diff carrer case. It is quite tight and you need some force to separate the two.

I got it apart - just had to "tap" a little harder. (Well also had to remove the shifting pieces). I'm not fixing it - I was just curious to see if I could figure out the tapping sound.

Again the gears look OK inside the tranny but the magnet at the rear has a ton of shavings on it. Of course this car has 185,000 miles so if that's the original tranny what else would you expect!

Thanks everybody for the tips and advice.

Next stop for this tranny is my local scrap metal recycler

Don't recycle it just yet!!
PM sent.

-Nick

Yea, come on....keep taking it apart and get us some pics

If you want inside pics I'll take some on Monday

Would love to see someone take theirs apart. that way I dont have to take mine apart just to see what it looks like.

lol

I have a blown one that I think I should take apart, could be fun. I wanna see inside ;-)

Awsome. Always more fun to break it then it is to fix it.

Here's the photos:

First I removed the side cover. Note the magnet and all the bits stuck on it.http://forums.pelicanparts.com/uploa...1208788322.jpg

This is the worst damage I found - this bearing race is toast.http://forums.pelicanparts.com/uploa...1208788401.jpg

This is an exploded view - I slid the splined coupling on to show where that goes.http://forums.pelicanparts.com/uploa...1208788718.jpg
http://forums.pelicanparts.com/uploa...1208788756.jpg

The main gears are mostly in the cast iron part of the housing.http://forums.pelicanparts.com/uploa...1208788844.jpg

This is the case with the differential gears set in place:http://forums.pelicanparts.com/uploa...1208788915.jpg

Here's one of the stub axles that your CV's bolt to, and how it goes into the diff assembly:http://forums.pelicanparts.com/uploa...1208788999.jpg
http://forums.pelicanparts.com/uploa...1208789023.jpg

So there you have it.

That actually doesn't look all that bad. I've seen some much, much worse then that.

You wanna see damage



http://forums.pelicanparts.com/uploa...1208815558.jpg



http://forums.pelicanparts.com/uploa...1208815607.jpg


http://forums.pelicanparts.com/uploa...1208815643.jpg

I turned my axles around and repacked the CVs at the same time - now I'm wondering if the CV joints were making the noise but it doesn't seem possible - It was a loud bang bang bang - one bang per revolution. Louder on acceleration and quieter on deceleration.

But anyway it works nice now and shifts way better, so I'm happy

This is by far the best thread for a transmission I have ever seen on this board. Good pictures and good descriptions of what I'm looking at. Thanks guys.

Since this turned into a more general thread on transmissions, I'll take the liberty of chiming in with a question. I just finished replacing a 3rd gear synchro and installing shorter 5th gear in an 89 S2 transmission (which is mechanically identical to earlier gearboxes to my knowledge). This was my first time inside a 944 gearbox. After reassembly and installatation, I found I've lost the spring centering of the shift lever. That is, it doesn't want to center on the 3-4 shift plane. It shifts through all the gears just fine, but without the spring centering, it wants to stay in whatever plane I shift it into (either 1-2, 3-4, or 5-R). Because of this, there's a greater risk of a missed shift. As far as I know everything went back the way it was supposed to, but obviously, something is not right.

When I manipulated the shift linkage on the gearbox before installing it in the car, it seemed to work fine -- it felt like it was centering on the 3-4 plane. (But I wish I had tried this before disassembly so I'd have some basis for comparison). But now that it's in the car, there's not enough force in the spring centering mechanism to center it with the shift linkage and lever attached. I know that makes it sound like the external linkage, but I think the external stuff is okay, and that something is wrong inside. It's as if the internal springs are not strong enough. Could I have assembled something wrong inside?

Any ideas?

The Haynes 924 manual has a great chapter on this.

Thanks for the pics and such. I've got a dying tranny in my 944 (well, it's been dying for years and just doesn't quit) and love to pull things apart, too.

Rob, if you look on top of the transaxle where the shift linkage attaches to, this round shaft is spring loaded. The spring keeps this selector shaft in neutral. Perhaps the spring came off when you took it out. Check out this pic.

http://forums.pelicanparts.com/uploa...1210676920.jpg

I think I have asked this before and it's a real stumper... and I will try again here seeing as there are a lot of people in this thread that know these transmissions...

Why does the front of the transmission have a bellhousing shape when it never bolted up to an engine? Why not just a small opening for the input shaft? Were these trannies originally cast to be adapted to a mid engine car too? Seems like a lot of wasted aluminum up there.

Bazar01,

Thank you for your thoughts.

I have to somewhat sheepishly admit that I found the problem last night. And it was an external problem, not the internal one I had thought. But it sure had me puzzled for a while.

The external shift linkage that attaches to the transmission case is rather complicated, and involves motion of several links that have to hinge, slide, and rotate. I had missed that there was binding in one of the joints -- shown in the photo below. That component is an aluminum sleeve that has to rotate slightly on a steel shaft every time the shift lever is moved laterally in the neutral gate. This aluminum sleeve is an aftermarket racing part that replaces the factory nylon or plastic part (apparently to reduce slop). It has to be able to rotate with minimal friction on the stub shaft that mates with the (long) shift rod. If it binds, it inhibits the function of the shift lever centering springs, which are indeed on the shaft you showed. I took it all apart and found -- somewhat to my relief -- that the internal components were all fine, including that shaft you identified, the centering springs on that shaft, and the reverse lock out mechanism that is part of the shaft. The reverse lock out, by the way, is a bizarre mechanism that defies description. It's very clever, though, and prevents going directly from 5th to reverse without first going into the neutral gate. Anyway, it was during this scrutiny that I realized what the problem was, and that I had missed it earlier.

The problem I had is unlikely to plague the average 944 transmission, because it involves an aftermarket part that's uncommon. What happened is that the aluminum sleeve had galled on the steel shaft. It needed to be disassembled, sanded, and lubricated. It was likely a progressive problem that coincidentally worsened at the time I rebuilt and reinstalled the transmission, so it had me worried I had made a mistake during the internal assembly.

Here is a pic of the problem part. Its the gray aluminum colored part in the upper left of the photo that the shiny shaft slides through. Sorry, I don't have a photo editor handy to show an arrow with...

http://forums.pelicanparts.com/uploa...1210714199.jpg

The reason for the "bellhousing" shape is that these trannys were originally designed and used for a front wheel drive car - Audi 5000. In that application the tranny did bolt up to the engine. A ton of stuff on these cars is pulled from the parts bins at VW/Audi - specially the early cars.

Finally I found my answer.

I never thought to think it was front a FWD car. Just doesn't seem like it would work, but then again the 5000 was sort of a boat so, makes sense.