Driveshaft Collar Nut

[AntiScope]

Okay so I've had a vibration going on recently. Increases with RPM and only happens when I'm in gear. I feel like my car is being held back somewhat, and feel the vibration coming up my seat. I thought it might be the CSB. So I replaced it and found that my driveshaft collar nut wasn't super tight in the first place.

When putting the two halves of my driveshaft together I noticed that they can still come apart, regardless of the tightness of the collar nut. Maybe this relates to the vibration? Maybe not. Can someone explain the purpose of the nut? It seems like it makes no difference whatsoever. Thanks

[jlevie]

The drive shaft must get a bit shorter to be removed or installed. Which is the purpose of the splines and collar nut. Vibration from under the car is almost always from binding u-joints in the drive shaft. A new or rebuilt drive shaft is the fix.

[AntiScope]

So tightening the nut secures it in place... that's what I figured but I cant see a noticeable difference. I probably need a new driveshaft.

[TobyB]

The collar nut just binds the splines so they don't wear. It makes life easier than it was
with the E21, where you had to take lots of stuff off the bottom of the car to get the
driveshaft off.
The 2002 didn't have the same problem, as there wasn't much under there
to take off in the first place.

But yeah, it should lock the driveshaft pretty snug, and if it doesn't, your splines MAY
be worn. I've never had an E30 problem with them, but in many other vehicles
with slip- joints, they can be a real problem at high driveshaft RPMs.

Including 2002's with Nismo transmissions when the shop builds you a
driveshaft with a slip- joint....

t

[dsphil]

If this is the collar nut you are referring to, there is a rubber bushing inside. Yours might be worn out.