Tranny or rear diff?
 

I have an 01 with the auto tranny with 160k on it. I know the tranny is done for but im worried that the rear end is on its way out also. When im driving around and go around a left hand turn the truck feels like it goes into nuetral. I can rev it up and nothing happens untill the truck strightens out then it will do a kind of bang and take off. Could this be a rear end problem or is it just in the transmission? Kinda strapped for cash and i need to keep limping around in the truck untill i get the cash saved for the trans. thanks for the help

my parents' suburban did that for a bit, then the rear grenaded. If you can spare the cash for diff fluid and rtv, crack open the rear diff and take a gander and see if anything looks wrong. When their diff went, it blew pieces of the ring gear through the diff cover, look literally like a grenade blew up inside the 3rd member. Hope you get it worked out!

Sounds like you need the filter changed in the trans or add some fluid. Thats exactly what happens when transmission sucks air.