Help Vibration Above certain speed.

[Gav240z]

For a while I've noticed a sound comming from the rear left hand side of my Z. It's started out small and it's very hard to hear due to the loud exhaust on my car.

The first noise I noticed was a scraping rubbing sound like a worn out bearing. I thought Wheel bearings but have not been driving the car last 2 weeks.

Now when I get to about 50miles + and I let go of the accelerator I notice alot of vibration. I thought driveshaft with the speed and all but it seems to have become worse and if a driveshaft was unbalanced I think it would only stay the same.

It seems to be constant anywhere over 50miles roughly 90km/h for the Aussies ;-).

Anyway here's my thoughts on what it could possibly be.

1.)Uni Joints either in driveshaft or halfshafts - This is an absolute pain of a job to replace unless you do the whole shaft but am not sure if these would cause excessive vibration. I noticed when I replaced my CV joints in my FWD Corolla a while back it eliminated some vibration.

2.) Wheel bearings - Not sure if these would cause vibrations but definately would cause that grinding bearing noise.

3.) The Diff - I have not checked the oil in it in a while and am uncertain as to if this would cause vibration. I will check it's level within the next day..

4.) Diff mount - Have to check it's condition but seemed fine when I checked it 2 or so months ago.

Any help would be greatly appreciated.

Gav,

[Zpeed]

gav... give me a call tommorrow, I'll be in ur side of the city, and i'll come and have a look. basically my whole rear end is new, and i'll tell ya what the vibration is...

if its the wheel bearings u'll hear more a clunk clunk,

id say it would be ur uni joints, most possibly ur driveshaft universal, its easy to change, i've changed mine twice, only costs like $20

the diff mount has around a .5cm give where you can see it coming over the actaul mount part, this is shown in the haynes manual... also the haynes manual basically says jack all about rear end noises, it just says to replace replace replace, which is basically ur only option... if it is ur diff, i can source you a used one that hasn't got no problems for less than 150...

talk to me on msn about it...

[Murph]

Originally posted by Zpeed

id say it would be ur uni joints, most possibly ur driveshaft universal, its easy to change, i've changed mine twice, only costs like $20

Where did you source that from? It's one of the many things on my list.

[240ZX]

test

[240ZX]

If by chance you've done a transplant in your series 1 Z (I am assuming you have an early 240Z), using an R200 differential and R200 drive axles (flanged type) from a 1981 to1983 280ZX and you haven't shortened the right side drive axle, you may want to check for U-joint binding on the right drive axle when the suspension travel places the axle perpendicular to the differential (the shortest length the drive axle will obtain in it's travel path).

[Brett240]

it still may be your tailshaft out of balance, mine went wildly out of balance a few months back, and kept getting worse and worse until the car was undrivable over 50mph