Driveline vibration help

[dbgrubbs]

Well, before I start taking things apart, thought I'd ask.

Lately I've been getting some driveline vibrations. Only under medium to hard acceleration and much worse when accelerating out of corners. The guibo is only about 1 1/2 years old and the CSB was in good shape at the time. I have gotten under the car and noticed that the guibo already has cracks and needs to be replaced again but is far from coming apart. I can also grab the driveshaft and seem to get no play back near the CSB. Other than the guibo and the CSB, the only other items I can think of are the universal joint, the differential or motor mounts. The differential is a 4.10LSD and is making no unusual noises. I glanced at the motor mounts and while they have some cracking, seem to otherwise be in useable shape.

Any opinions or help?

Thanks
Don

[jlevie]

A vibration that is worse when the drive train is subjected to high torque loads is usually the result of binding u-joints in the drive shaft. The fix is to replace the drive shaft and CSB (and guibo in this case).

[Jonny Cash]

How does the trans mounts look?

[dbgrubbs]

A vibration that is worse when the drive train is subjected to high torque loads is usually the result of binding u-joints in the drive shaft. The fix is to replace the drive shaft and CSB (and guibo in this case).

That's what I'm expecting to find too.

[dbgrubbs]

How does the trans mounts look?

Tranny mounts are fine. I bit cracked but still in good shape.

[dbgrubbs]

Ok, took the driveshaft off and took a good hard look. I really can't remember if I replaced the CSB at the same time as the front guibo but from the looks of it I did. Nothing wrong with it at all. The rear universal joint is a bit notchy but still moves easily w/ no signs of binding. The front guibo is in much worse shape than I thought. No chunks missing but looks as if it's about to fall apart. Could this be the lone source of my noise and vibration? How bad does the universal joint get before it starts to cause problems (vibration and CSB problems)?

Thanks
Don

[Maddog]

Check your motor mounts, especially if it has a lot of miles. I know on the M10 E30's, the mounts have a tendency to fail around 100K. The M20's are sturdier, but like all rubber insulated parts, they do not last forever.

[dbgrubbs]

I ended up putting it all back together with just a swap to a new front guibo. I guess that's all that was wrong with it. Even though the old one didn't look awful, it was coming apart and now the noise is gone with a switch to a new one. I guess it doesn't take much.