Transfer Case?

[suburban2500plowz]

ok when i accelerate and get on the gas i get a clunk from the front end. As you hit the gas and the 6.0 throws you in the seats it clanks and clunks but only once or twice every time it accelarates. i went under the truck and grabbed the front driveshaft and noticed ther was some slop int eh transfer case like a inch or so in each direction and i was almost able to simulate a clunking could there be an issue with the transfer case it does have alot of miles on it or is there an easy fix the u joints seem to be tight still????????????????

[Riverjet502]

Sounds kinda like a dry socket on the U-joint..Take a real close look at it. Better yet take it apart, drop the drive shaft and feel if the slop went away on the output shaft.