jack

I have been told my transfer case may be making a the "gear meshing noise".
I would like to become more informed as to diagnosing transfer case problems
on a 1991 Grande Cherokee 5.1 liter Jeep.
History.
1. Front Differential blew . Rebuilt by Mechanic.
2. Four months Later Real Differential blows Rebuilt same mechanic.
A. Possible cause mismatched Tires.
3. A noise remains It occurs after the car is driven, when in Park, sounds
like possible gear meshing low pitch, intermittent. During driving when the
car is steered to the left you hear a higher pitched whine. like a power
steering pump low on fluid.
Any help would be great.
thanks
pd