How do I know if I have driveline vibration? Installed a new 3" lift two weeks ago and now I'm starting to hear a weird rythmic sound coming from the rear. Almost a ticking or thumping sound. Haven't crawled under to investigate yet.

 

You would know if you had vibes, you'd feel them. Sounds like your rear u-joint was old and with the new angle with the lift it ain't happy. May just need grease.

 

Doesn't look like my u joints are greasable. Found it is very loud when I let off the gas. I can actually feel it .

 

Block the tires and put it in neutral and see if you can move the drive shaft. It shouldn't move but just a tiny bit. This will let you know if the u joints or pinion bearings are bad.

 

Ujoints werent the problem. Somehow my wheel had become loose, and thats where the vibes were coming from.