I just installed a new rear end with 410 posi in my 64. I went to test it out the other day and everything was fine until I hit 3rd gear and got up to about 5000 on the tach (about 95 mph) and the whole car got a low pitch vibration in it. I slowed down and it went away. I tried it again and it did the same thing right at about 95 mph. I can tach the car up to 8000 in 1st and 2nd but not third. Also it does fine in third at lower rpms. Any help would be great..


Thanks...

Try to simulate it on securely positioned jack stands under the axle housing. You won't be able to simulate load though. Then try it in each gear and find out if it's speed or RPM related. Sounds like a driveshaft vibration. If your U-joints are free, remove the rear joint from the yoke rotate it 180 degrees, re-install and try again. It's a good starting point, Rob

Thanks , I will give it a try as soon as I get the new fuel system installed...thanks for the info...



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Does the vibration change with engine RPM's? Get it up to about 100 (not to break the speed limit of course http://www.chevelles.com/forum/smile.gif ), put it in neutral, and coast back down to 95ish.

Does it change with slight left, or right turns?

I think I need to install a drive shaft loop before I start to play with it too much. Thats next up anyway. I already lost one about a year ago. Lucky for me the rear u-joint went out, not the front.

so what has changed? the driveline was down and the rearend was changed, no vibration at 95 before? check the driveline, and the driveline angle, if they are ok and nothing else was changed, its in our recon rearend