<E36> Vibration at higher speeds.

[marcva]

Im continuing to chase my vibration at about 80 mph on the highway.

To date, I have

Checked balance on all 4 tires
rebuilt rear calipers with new pistons
rebuilt parking brakes (return springs were shot...they were overdue).

The problem is that it seems intermittent. I can run at 90 and things are OK, then a vibration will build up. It can get unpleasant if I don't back off. It feels like a wheel velocity cadence. so something in the drivetrain...

Trying to think of other components to consider

1) Doesn't seem like a bearing since it doesn't change character with direction.
2) I have had the drive shafts off of the Diff to do spring changes, might one of those joints be drying out/going bad? How to diagnose?
3) Could it be the diif starting to have problems? Check the fluid for issues? drive with seats down to listen for noises?

I can get the rear up on stands to facilitate any testing.

Thanks.

Marc Plante
E36 M3/4/5 186k
Vienna, VA USA

[shadowpuck]

marc - i've been pondering this for awhile today and, sadly, don't have any really good thoughts (some would say that's a common happening - lol)...

anyway.

is the driveshaft original to the car?

can you feel it? in front of you? beside you? behind you?

[marcva]

behind me. Speed dependent. gets worse pretty drastically above 80 mph (open spaces of highway, yet, intermittent. No real noise, just a vibration sensation. Does not vary on and off power. If I lift and take the car out of gear, the issue is still there. All still leaves driveshaft in the realm of possibiity. How can I diagnose with jackstands. pick up the back and turn the wheels and listen to the center bearing for rubbing?

Thanks,

Marc

[shadowpuck]

here's your other thread on this - can probably combine these so its all in one place....

https://www.bimmerforums.com/forum/s...-higher-speeds

driveshaft would seem a good suspect to me if its original - but, i'm not quite sure how to test it.

[LittleHemi]

So I had an 1992 E36 325is and it was two issues for me that fixed the problem. First the center bearing on the drive shaft rotted away and needed replacing. The second issue was the Flex disc that connects the drive shaft to the transmission. Changing both of these for me solved the problem. I paid around $100 on the secondary markets for both parts. The job took me 3 hours because of the center bearing but other than that its fairly easy job!