Sounds like engine rebuild will be needed. Former owner didn't take care of the machine??? Sprockets do look way too sharp----when you get the engine fixed and everything else works good-----then you can do track work but maybe use it a little first.
It looks like a nice dozer overall and a handy size to move around.

"A machine you build yourself is a vote for a different way of life. There are things you have to earn with your hands."