[novagard]

I have a similar problem with a 95 GC; same drivetrain. Was told by a mechanic and several forum readers it is the viscous coupling in the transfer case. Rebuilt case is about $900 and the part alone is $350-$400. Mine does not seem as severe as yours. Only thumps and bumps at very low speeds (parking) during sharp turns. Good luck. I'm going to ride mine until it craps out