I have a 1993 chevy suburban k2500, It developed a very loud and random clunk while driving, It does not matter how fast, up hill down hill or flat, and sometimes kicks itself out of 2h (have not tried 4 wheel drive) ive changed the actuator nothing changed. any ideas would help i'm at a lost

 

I'd just start by checking the engine & trans mounts, U-joints, etc... Do you have any vibrations? Does it happen when you let off the gas, accelerate?

 

I can't imagine anything other than something in the transfer case being the cause, especially with it kicking out of 2wd.