I have a L120 riding lawn mower that is 2 1/2 years old. It doesn't
move forward or in reverse very fast. I replaced the drive belt and
that seemed to help some, but it's not right. It almost seems like
something is slipping inside and it gets worse the longer it runs.
Almost like the oil in it gets warm and allows something to slip.

Has anyone ever replaces the fluid in one of these hydrostatic
transmissions?

Thank you.

Swede