josephsc

I think the transmission on my 944 ate itself this morning. I was half-expecting for this to happen because I got a 968 engine mated to an older/weaker tranny -- but not within two weeks of my other car going out of commission! (other mishap)

Anyways, I'm going to tow the car home and start ripping at the tranny, but I want to get some opinions: just to make sure it's the tranny and not some other part of the drivetrain (like the clutch or the torque tube). This happened while I was downshifting coming off the freeway. I got extremely violent shaking when the transmission in gear -- at first I thought I had a flat tire or something but turned out to be not the case. I went a little ways to diagnose what's wrong, but basically extreme shaking in gear - no shaking when coasting with the clutch pressed in. Well, almost no shaking -- I can hear some clicking noise that seems to be depends on the wheel speed. I'm thinking the tranny, but can it possibly be the clutch instead or something else?

nine-44

Kinda sounds like a CV joint, usually a tranny will make a gear whine or just break. I'd be looking at the CV joints first, see if the shaft wil slide freely side to side with no binding. Or possibly jack it up and see if it spins freely. Did it break, like no go in any gear, or just making hella noise?

josephsc

Hey -- great suggestion! I hope so. I repacked an old CV joint just last year. But wouldn't the CV joint continue to cause vibrations with the clutch disengaged?

Swagger93

not necessarily, because there is no load. if hes in gear and coasting you have the load from the compression of the engine. Ive never heard of a CV joint causing violent shaking though. Talk to 944T4ME, he had a torque tube failure in his 86 951.

tifosiman

Check the CV's first, as that is easiest. Then, if they aren't the issue, pull them, then pull the access cover on the trans and look inside for shrapnel.

josephsc

I just towed the car back home and had a little more diagnotic/play time. I doubt it's the CV joints. Currently, it's very hard to get into any gear, and all I get on 1st or reverse is grinding noise from the rear. I'll know better once get underneath the car...

This was to be expected, but I wasn't expecting it to be so soon! 5000miles on a 968 engine, in case anyone's going this route.

tifosiman

Don't feel bad. Autocrossing on a stock n/a trans with a mildly worked n/a motor grenaded mine in about that many miles the last time. My car is on it's 4th trans and it only has around 82K on it. The stock n/a trans pinion gear cannot handle dynamic loads.

josephsc

Well, I only had time before it got dark to drain the tranny to find it full of metal shavings (and I replaced fluid only 5K miles ago...). Not a good sign. There's also alot of "slop" across the wheels, I can turn one wheel a few degrees before the other wheel starts turning -- I don't remember seeing this slop before...

ERAU-944

that slop's there in my cars too, i thnk that's normal. sounds like your diff is ok. i hope its your clutch and not your tranny...

nine-44

slop yes, not too much tho, metal in the gear oil, no, not good at all!

Porsche-O-Phile

Doesn't matter - to change the clutch pretty much requires removing the trans. anyway just it would be more expensive. In his case though (with a 3L engine) he might be well off just swapping the trans. out anyway. If I were in his situation and the clutch started to go, I'd just swap it then. Why do that job twice?

NZ951

I wasted my n/a tranny with only a throttle cam and k&n installed! Those things are junk.

Luis de Prat

My guess is the clutch has gone bad. What kind of clutch is on this car? Original rubber centered disc? Spring centered replacement? When my rubber centered went started to go bad, it had violent shaking in gear. This is another reason why it's a good idea to take the racers' advice (e.g. Z-Man) and only use the brakes to slow down the car.

I'm really sorry. Hoping for the best and that everything works out!

tifosiman

I'm gonna lay $20 down on the table betting that it is the ring and pinion gears. Time to pull the side cover on the passenger side and inspect. It will probably look like this:

josephsc

I'm putting my money on that too. One other sign was that when the tranny went, I smelled something nasty (kinda like methane/natural gas smell) in the rear of the car. Got the same smell when I drained the tranny oil.

Last night, just dropped the right axle, removed the flange shaft (held with an allen hex bolt), and undid the 9 bolts on the cover. It should come off now, right? The cover seems stuck on there -- can I start prying / banging / beating / bashing / pounding / hammering / smashing on the darn thing?