Looking for some wisdom!

Just finished installing a 3inch lift, took the jeep out on the road for the first time with it installed, and at about 20-30kmh, I started getting really noticeable vibrations coming from the rear end. The thing I found strange with them is when I got on the gas, got it up to about 50, they went away. They only come back when I'm in that 20-30 area and when I'm slowing down to a stop.

Does this sound like driveline stuff to you guys? I've never experienced it before so it's hard for me to tell what exactly is going on, cause to me it almost feels like something in the drum brake assembly is catching or something like?

 

Did you stretch brake cable tight by lifting causeing shoes to drag ?

 

Could be a definite possibility. How would you go about remedying that?

edit: the more I think about it, I dunno if it's brake related. It wasn't doing it at all up in the trails we were at tonight, only when I'm driving on the road.