I have a bad vibration @ 90+. I have new wheels and tires....no help. I have an LS1 driveshaft.....no help. When I coast @ that speed in neutral the vibration doesn't go away. I had a pro alignment. They had to max out the camber adjustment on the passenger side , but still could not align that side due to a bent spindle. I really don't think that is my problem because I had the vibe before putting those on

If I am in neutral does the driveshaft stop rotating?

What about the rear internals...does that stop rotating in neutral even though the wheels are spinning? (I know my gears are about shot)

Can multiple bad ball joints cause the vibration? (I am changing those ASAP)

Thanks for your thoughts

 

If you have a bent spindle I am guessing you hit a curb. If you hit a curb with your rear end as well you might have bent an axle back there. (this is usually accompanied with a noise but not always)

Does it fluctuate with RPM or just speed??

 

I did not hit a curb. LOL. I purchased the LS1 upgrade from a junkyard that appaently pulled them from a front end wrecked vehicle. Nice huh?

When the alignment was done they checked the rearend also. No problems there.

Oh yeah, it is fine below 90, but any speed above that it gets worse.

 

In response to your earlier questions. When you put it in neutral, your driveshaft is still spinning, the transmission is no longer providing power to it though. The rear end gears are still spinning at the same speed as well, so if those are shot, then you might have a problem there.

 

I've got the same problem, but mines at the 70mph mark, probably due to the 4.10 gears... mine's so bad it feels like the whole car is falling apart...

I've been trying to figure it out for a while to no avial... if you figure it out, be sure to post, I'd love to know.

 

Have you removed your driveshaft recently? If it is not reinstalled in the exact location it was removed it will vibrate. It will vibrate really bad if you installed it with the weight 180 degrees from the original location. If your weight has fallen off the driveshaft, you will need to get it rebalanced. Try re-installing the driveshaft 180 degrees from the current location to see if the vibration lessens.

Also this is a trick I learned somewhere, can't remember where. To determine where a vibration is coming from, jack up the rear of your car so the wheels are off the ground. Run the car up to the speed of the vibration and note it. If there is no vibration, it's probably in your front end. Then, remove the tires and do it again. If the vibration is still there, the problem is not in the rims/tires. Then remove the driveshaft and do it again. If the vibration is still there, the problem is not in the rear end/driveshaft. This will help pinpoint your problem.

 

I got an LS1 driveshaft to get rid of the high speed vibration, but I still seem to get a howling effect at 90+, not so much of the vibration I had from the lt1 driveshaft but a noisy effect is there. Is that what you are getting too? Maybe you need to get it balanced?

 

It could be a driveshaft balance problem, but first what I would do is reposition the driveshaft in the transmission, say 3 or 4 teeth clockwise, and see if it reduces the vibration/noise or increases it. If it gets worse, move 3 to 4 teeth counter-clockwise from your original install location, zeroing in on a location that will provide the least vibration. Eventually you should find a location that either completely removes the vibration or at least quiets it considerably. If this doesn't help, something on the vehicle is out of balance, whether it's wheels/tires, brakes, driveshaft, transmission, engine....