I bought a brandnew F525 back in about 1991, liked it a lot but by the time it reached 700 hours the engine was leaking a lot of oil, talked to a couple John Deere dealers about fixing it and they said junk it because the labor to fix it would cost more than the mower was worth. I sold it to a friend that fixed it himself and he is still using it.
One of my brothers bought a new one about 1993 and his lasted 1,500 hours before the same thing happened to his.
Agree The traction wasn’t very good but that rarely caused me any real trouble, just don’t try climbing steep hills when the grass is wet.
It has a Kawasaki engine that uses the same regular motor oil to run the hydrostatic wheel drive. I am unaware of any other engine hydro system that is designed to work like that.