I've noticed a grinding/vibration sensation when I let off the gas pedal. I can feel it in the pedal if i have my foot on it. This is all noticable when i let off gas going anywhere above 30mph.

i recently had a lift installed . but i had everything aligned at the shop.

its a 2wd so no CV's or anything. no diff drop.

the lift was 2.5 in the front and about 3-3.5 in rear

 

check u joints in driveline vibration when u let off gas is usually the slack in your u joints (wornout needle bearings) if not try an get more details on problems