How much rotational play is acceptable for the front flex disk ('91 300SE)? While I had the car on the lift this weekend, I noticed the driveshaft would rotate back and forth as if the holes in the disk were enlarged. Otherwise the disk appeared to be in good shape. By the way, the shaft didn't have any front to back play.
Thanks for the help.
Steve

Sounds bad to me. Your driveshaft coupling has a softened area around the bolts. There are numerous holes built into the disc at these points. This area breaks down and the sleeve and bolt move around in a much larger hole. Get the new disc and you will see what I'm talking about.

Thanks. That's what I thought, but always nice to double check.
Steve

Did you actually watch the disk, or just the shaft? When the car is in park, it is likely to have some movement in the drive shaft.

I had the car on the lift, in park. When the shaft was rotated the disk appeared loose, I didn't notice if the disk was turning on the trans tail tho. It's hard to quantify the amount of play, but I'd have to say it was moving ~1/8 to 1/4"on the driveshaft side. The disk didn't show signs of checking or rot, but I thought this was a lot of movement. Also the car has a slight "bearing" noise at speed.
Thanks
Steve

There should be no play in the flex coupling between the trans output shaft and the propeller shaft yoke. Having said that, there is a small amount of "backlash" in the trans when in park, suprisingly about what you describe. If the flex disc is failing, you should be able to tell by holding the output flange in one hand and twisting the propeller shaft with the other. If it is worn out, you should be able to tell..