I'm new to this. I got a 850c case dozer you can work if for about 15 to 20 minutes and it slows down pushing but engine runs strong jus can't get out it's own way I can take it out of gear for about 2 minutes and put it back into gear and it will move for a bit then stop.I've changed all filters and fluid
Maybe a torque converter problem, or even a weak pump. but I believe they have a suction filter inside the tranny that could be clogged up with gunk or collapsing.