Vibration at Speed??(searched)
 

I have a vibration from the rear end area that seems to only be noticeable at 45mph+. Sounds like its coming from the differential but I'm obviously not able to know for sure.

What are the symptoms of a shitty rear end(no pun intended)??
I have some other random clunks and noises that I have yet to source.

Any info helpful
thanks
T

Does it not want to grab sometimes? I had a differential going out on me in one of my old 240's and the problem was the differential.

Could be bad diff mounts - they are fluid filled, and if one or more collapsed, it would transmit any drive-train noise to the body.

What frequency is the noise? Is it at wheel rotation frequency, driveshaft rotation frequency (~three time as fast as a wheel-related noise), or gear noise (higher-pitched than either of the other two)?

Dave

Also, does it only happen under acceleration? Or is it constant under all conditions?

could be simply the tires need to be balanced but could be u-joints in the driveshaft failing or CV joints or internally in the diff.

first place i would start is rotate the tires and see if it moves to the front of the car, if it does then you know you have a tire balance issue or bent wheel, corded tire, etc.. if it doesn't change then you will need to inspect your u-joints, CV joint boots and pinion shaft play and if needed jack up the rear end and run the car and see if you can notice the vibration with no load on it. if it is only a loaded issue then it will be a little more difficult to pinpoint, at that point i would visually inspect the shocks for leakage and check the rear diff oil for metal indicating that the diff bearings are failing.

if its a vibration/shimmy you work in this order

1. tires, condition? balance? rotation?
2. bent rim?
3. loose/bent/bad suspension, ball joints, pillow balls, bushings
4. alignment
5. bad u joint/out of balance driveshaft, bad axle/cv joint

a diff could cause a vibration, but its a little unlikely, and it would be most likely making really bad noises too

This makes a lot of sense.