1998 Dodge Ram pickup

I hear a clicking noise when turning. Could that be the limited slip differential.

Possibly, sounds like you might have a lock-right or detroit rocker installed in the differential case. They are traction modifications. Did you buy your truck used or are you the only owner.

P.S. If you do have a locker modification installed. The clicking is normal

I had the same problem with my 99 Ram. I tracked it down to a heat shield next to the passenger side exaulst manifold that was tapping the suspension during left turns after a front brake job. A slight bend toward the exaulst manifold silenced the heat shield.

if you have an aftermarket dif, then the clicking is normal, assumeing that it's coming from the rear axle. if your truck has the factory limited slip, it should NOT make noise.
try to track down exactly where the "clicking" is coming from, if you have a 4x4, and the noise is coming from the front, it could be a U-joint starting to go out.

yeah what he said, try to find out where the clicking sound is coming from and exactly when it does it and does not do it. eg. moving, stopped, turning, etc.