I have a 97 ram 2500 with a 360. It is making a very loud clunking only when in 4x. Put it up on stands and it only makes the noise when the wheels are cranked to one side, happens on either side. Tried to find out where the noise is coming from but it is hard. Kinda sounds like its comine from the transfer case, but hard to tell if its just the vibration. It is a very loud clunking. Pulled off the front plate on the diffrential and everything looked like it was ok. Any idea???
Thank you for all help.

 

Probably one (or more) of the MANY u-joints in the system. Two in the CV joint at the t-case, one at the other end of the shaft, and one at each end of the axle. have a look at 'em. Any play or binding is reason for replacement.

 

When I gram the front drive line and wiggle it there is about what seems to be about 1/4" of play. Could that be causing the very loud clunking? Wasnt sure if that was normal amount of play.
Thanks.

 

If you can MOVE the shaft 1/4 inch, need to find where the slop is, and FIX it. If that is rotational movement, that is pretty normal, and you need to look elsewhere for the noise.

Jack up the front end, (jackstands please.) and spin things. See what you find/hear.