HELP...bad vibration?

[cb18201]

when im on the highway doing about 70 i get real bad vibrations in my driveline, my shifter vibrates and makes a buzzing noise and the vibration causes a humming sound, a mechanic looked at my car and said that my axles have play in them, he put my car on the lift an moved my rear tires with hids hands side to side to show me. is this normal to have play in your axles? also my drive shaft you can turn about an inch each way before it stops or makes contact. when im on the highway and i take it out of gear the trans still makes a little noise but no where near as bad as when in gear and the vibrations are still bad from the rear so i know its not the tranny, it has to be something with the driveshaft or rear i think. do you think the shop that did my gears messed something up? it never vibrated or did this before my gears. i talked alot a few other people with 430s and they have no vibrations problems at all. i brought it back to the shop that did the rearend work and they are looking at it right now but i wanted a few second opinions from other people who might know. thanks

 

[stang_gt_1994]

The driveshaft is out of balance. Try unbolting it and then putting it back on it a different position. It could be the reason. Try this first and see if it fixes it.

 

[wytstang]

Look at the U-joints they maybe on the way out.

 

[slytherin]

Start with the uni's, then check the DS it may have thrown a weight if so buy an aluminum DS, that and get your tires and wheels rebalanced to see if that might cure it.

 

[Killercanary]

I had the same vibrations and mine got a lot better, though not totally cured, by putting in new axle bearings. Also, if you can move the DS an inch, it sounds like U joints AND that you have too much backlash in your gears. I'd definitely inspect the rear end as this point.