Suzuki Jimny Clutch Problems

Ihave a 2000 jimny that has a loud grinding noise that comes on and after 50 yards theres a loud thump and noise goes it does not happen daily but is a pain when it is there I have been told possible transfer box .can any body help

Driving along when suddenly the engine revs high and I lose forward drive. Appears to select any gear, clutch appears okay but no forward or reverse drive. Thanks

Driving along at 40mph speed limit change to 50. As accelerating to speed up car loses power in 4th gear sounding bogged down, down change to 3rd gear and rev counter goes right up but still loosing power, pulled over and let sit for a whil...