944Ross

Is it possible for the driveshaft to be so far back in the TT that it is out of the pilot bearing, but still clears the transaxle input? If this were possible, would it also be possible to pinch down the coupler? I guess this boils down to, how much of a gap should there be between the driveshaft and the trans input shaft? Is there a spec?

Black Sea RD

The drive shaft has a groove around it at the transmission end. This groove is where the bolt goes through when you pinch down the coupler onto the drive shaft. If this groove is out of alignment the pinch bolt cannot be put through the coupler.

The best way to set the correct distance is to measure from the mounting face of the transmission to the middle of the cutout of the transmission input shaft. Then use this measurement to set the middle of drive shaft groove to the edge of the aluminum transmission housing where it mounts to the transmission.

HTH,

944Ross

I was wondering if the DS was all the way back to the trans input shaft, if the bolt could be put thru in an area clear of the splines completely? Both clutches I've done, it seems like the distance between the DS and the trans input was no more than 1/8" or so.

I'm struggling with what could be wrong with a clutch job I finished a couple months ago. It chatters badly, to the point that if I don't rev-match on a downshift, it about shakes the car apart. The DS being out of the pilot would certainly do that. If it isn't something like that I'll have to pull it all apart to figure it out

Black Sea RD

I just checked one of our 944 drive shafts (DS) and there really is no way for you to easily put that bolt through any other area but the DS cutout.

A few possibilities could include the DS front nub not being engaged due to the pilot bearing itself fragging (a possibility if you didn't change it), the DS front nub wearing and not holding itself in the pilot bearing, the front bearing unit in the torque tube has moved or the flywheel/clutch assembly has worked loose.

It would seem you will probably have to go back in. Would recommend not driving it much more since you can be causing damage to more hard parts doing so. I would check the DS/Trans input shaft connection to start since it's the easiest to do and go from there.

Regards,

944Ross

Thanks for the responses... Yeah, I'm pretty much resigned to pulling it all apart. Why risk it?

951Saga

Adding to what Constantine said. When the transaxle end of the DS is centered in the front TT coupler access hole the DS should be in the proper position.

Also with the bell housing on the motor you can measure from the pilot bearing face to the TT mounting surface of the BH, then measure the distance the DS extends from the front of the TT. This will give you the distance the DS is in the pilot bearing.

Photos tell the story…

944Ross

Great pics! I can see there just isn't any way the coupler could be pinched down with the DS far enough back to be out of the pilot bearing. Ah well....

944Ross

Update: I bit the bullet and took it all back apart. Nothing real obvious wrong, lots of little things. Oil and metal shavings hiding in the step's inner groove on the FW; can't believe I missed that. One of the coupler's bolts was somewhat chewed up like it was hitting splines. The clutch fork had a flat spot worn on each finger. The PP was not real flat across its face.

So I used a whole can of brake cleaner on the FW, replaced the clutch fork with a better used one, and block-sanded the PP face till it was making full contact across the face. Also scrubbed the disc with brake cleaner and a stiff wire brush, it had a glazed look. When I did the coupler bolts, I started one, then the other and slid it back and forth as I tightened so both bolts were centered on the cut in the splines.

Back together and all is well! Amazing how fast it goes the 3rd time...

Black Sea RD

Great news that you got it all fixed!

When I did my first dual disk clutch on my track 928, I did about 5 clutch R&Rs in a row until I got everything right. Yes, they did get faster as I went along!

Congratulations on getting it done and now you have a wealth of information for the next person with these kinds of problems.

Cheers,

944Ross

Thanks for your help, Constantine!

BTW, I don't know if it's news, but clutch forks are out of production now. Don't throw any away!