I have noticed a few times that when I back up to turn around, that when i slowly accelerate to go backwards about 30 feet, that when I let off the throttle, the truck kind of surges and few feet. Im not sure if this is the engine surging or the tranny. This also happened this morning while going forward. Im just barely on the gas, then let off, it jumps, not far, but it doesnt feel right. I dont notice it all the time, mostly when going uphill. Is this some small indication of something, or does it seem normal? The truck is an 04, with 124,000. Stock everything, with the exception of a 4inch lift.

Mine does that when I let off the gas in reverse sometimes too.