Vibration in rear any speed above 85MPH

[rickyb916]

Not sure if this belongs in suspension, driveline, etc so here it is.

1991 318i(s)

Getting a vibration in rear of car above 85~MPH.
Also getting a clunking like noise when slow turning(pulling out of a tight parking spot) from the rear.

What I've replaced:
-AKG 95a subframe bushings (before replacing these, car wouldn't go past 65 w/o vibrations)
-AKG 95a diff mount
-Transmission mounts (one was ripped in half/driver side)
-Rear Shock mounts
-Sway bar bushings(rear)
-Sway bar links (rear)

I was thinking the guibo or CSB, but when I looked at my guibo, looked brand new, not a single crack, rubber didn't look distorted or worn at all.
I snapped pics from the front and rear of the drive line to better see the CSB without removing exhuast/etc and bushing doesn't look worn either. when the car is in neutral and I grab the driveline it has a movement of about an 1/8 of a turn clockwise I believe and it will go back the other way 1/8 of a turn, but no play in any other way.

What else could this be?
Trailing arm bushings?
Rear ujoint shot?

[ELVA164]

1/8 of a turn sounds like a lot to me as far as slop in the diff goes. LSD? That could cause the clunk as well. The vibration sounds like either the CSB or more likely an out-of-balance wheel. Why are you above 85mph?

[FLG]

First place to start is getting wheels balanced. I always go to track oriented shop with a road force high speed machine.

Sent from my SCH-I545 using Tapatalk 2

[TobyB]

What kinda vibration?
Thumpa thumpa thumpa,
or whirrrrrrrr?

Whirrrrrr can be a bound u- joint in the driveshaft, or a driveshaft that hasn't
been pretensioned properly. Or a front bushing that's shot. The one that
fits onto the trans output shaft...

t

[rickyb916]

1/8 of a turn sounds like a lot to me as far as slop in the diff goes. LSD? That could cause the clunk as well. The vibration sounds like either the CSB or more likely an out-of-balance wheel. Why are you above 85mph?

Open diff, I'm getting another 4.10LSD in a month either way, so I don't care too much if this diff is toast or not.

I live in California, everyone drives 80 on the freeway. Also 'closed' road (BFE roads) spirited driving.

First place to start is getting wheels balanced. I always go to track oriented shop with a road force high speed machine.

Sent from my SCH-I545 using Tapatalk 2

I've had all four balanced multiple times.

What kinda vibration?
Thumpa thumpa thumpa,
or whirrrrrrrr?

Whirrrrrr can be a bound u- joint in the driveshaft, or a driveshaft that hasn't
been pretensioned properly. Or a front bushing that's shot. The one that
fits onto the trans output shaft...

t

Mix of both, but it's not a whirl like a bad diff (had that problem with my jeep's diff). Front bushing/guibo is in like brand new condition, not a single crack and rubber isn't faded or worn.

I'm either at the csb or ujoint, just don't want to drop 300-500 on a rebuilt driveline :| but if I have to.

Would bad trailing arm bushings cause anything like this? they look cracked and the only bushing I haven't replaced in the rear. I'll get a video of the 1/8th 'play'.

thanks guys

[ELVA164]

My vote goes to the csb at this point.