Was out mowing last week, lift started moving slow, checked my hydraulic dipstick and it was low so I added fluid to it mowed for a few hours, lift started moving slow again checked Hyd. fluid it was low so added more fluid. Couldn't see any where it was draining out. Had some one tell me to check level in gear case I did so and it was over filled. I was told that the Hyd. lines that run thru the gear case probably had corroded and needed to be changed? I was told tractor had to be split to fix them, is this a fairly straight forward job that I could do or should I leave it to someone that works on tractors all the time?