Back again...w/ D20 Komatsu

Hi all- have a question about a D20 komatsu. It had a sticking track that we adjusted the linkage and it worked good. It recently did it again and was parked. Now it wont go anywhere- you let the clutch out and it will almost stall it out but wont move. Checked all fluids, checked parking brake to see if stuck. It wasnt making any strange noises before hand from what ive been told. Could it need clutch adjusted or does it sound like something else. Any thoughts appreciated.

Back again...w/ D20 Komatsu