I had trouble with the clutch in my Agracat 2920 (Jinma 254) after I picked it up with only 8 hours or so. It turned out the pivot pins were all corroded and stuck. It took a couple of hours to slowly work each pin loose with penetrating oil and a small ball peen, tap tap tap! After I got all the moving parts free it worked like a champ and hasn't slipped a bit since. I figure salt air from shipping and possible water leaking into the housing through the small inspection plate opening allowed moisture to accumulate and not dry out easily. I also drilled a 3/16" drain hole underneath the bell housing to get rid of all the accumulated oil spray and allow any further water that might enter a path out.
So far so good, before the clutch would slip if I even tried to load the bucket, now I can push over 8" trees without any slippage.