Took my jk in to the dealer for a leaking rear pinion seal. I got it back with vibration between 40 and 65 mph. I brought it back and they said a tire was out of balance. When I picked it up the second time after they balanced the wheels, it was still vibrating. I haven't brought it back yet, they seem to be idiots.
Any idea what they could have done to cause the vibration?

I didn't have any vibrations at all when I brought it to the the 1st time.

 

My guess it's a driveshaft vibe. Maybe they lost a weight on you?

 

I didn't see any weights missing on the drive shaft. I might just pull it off and see if the the vibration goes away.