I have a bad vibration I cant get rid of. About 6 months ago I went from 3.08 to a 4.10. Also installed a zexel torsen Posi, and new axles. the Vibration is only slightly noticeable crusing around town. Down the Hiway It is a little worse , Down the freeway is terrible. I cant go any faster than 60.
Here are some clues that might help.

It does not matter what gear i am in.
It is not related to engine RPM's
I Have already tried balancing the drivline.
I bought new tires and rims.
New Tranny mount.
New Clutch (t56)

The vibration Is 10 times worse when I press in the clutch. When I accelerate or slow down the vibration is not as bad. When I maintain the throttle and I am not going up or down a hill it is worse.

Please help if you can It getting expensive

 

Hmm, i have a very similar setup with 3:73's. I get the exact same thing when i go 80.. at 85 it stops but sometimes stays until 90. Anyway, i had the drive shaft balanced and that isn't it. I think its just that the steel DS are crap. I have heard that the AL ones are much better. Have you had the tires balanced? Perhaps the axles are bent. I have gone through similar options but i can't shake it (no pun intended) I have yet to buy the aluminum DS. PLEASE let me know if you fix this!!!

Oh, does your vibration go away above a certain speed?

 

It does not go away at Higher speeds. The tires were recently balanced. The Driveshaft was balanced today. What really sucks is, it is worse after the driveline being balanced. I even pulled the drivline back off the car and took it back to the shop to have it rechecked. Tomorrow I am going to try going to the top of a long steep hill and taking the drivline off then Coast down the hill at freeway speeds.

 

I hope you are not serious about the hill thing. What about the axles? Are they new or used? Do you have disc or drums? Perhaps one of the weights on a drum has fallen off? Other than that i am completely stumped. Maybe its time for a pro to look at it?

 

Yep Im serious about the hill thing. If I take the drivline off and I can reach the speed that it normaly shakes I will know if the drivline is the problem. The axles are new from drivetrain direct.

 

Since we both have the Zexel Torsion posi, i wonder if thats the problem? It could be that its only balanced up to a certain RPM but they higher gears it reaches its limit. I don't know if that is the case, just a thought.

 

Maybe something with the front suspension? I had a bad front driver side inner wheel bearing and it made a godawful vibration. Does it vary in loudness when you corner? If it does I betcha its a wheel bearing, or maybe a tierod or center link. You can check for bad wheel bearings by jacking up the front of the car and trying to push in on the top of the wheel, if it feels like it has play on the spindle shaft, then its probably a bearing.