I'm sure that the 425 uses the same valve cover or at least the same type as the 445. The seal is a square section packing (like an O-ring only square instead of round) that fits in a groove in the valve cover. At 1600 hours, my right one has never leaked. The left cover, on the other hand, seems impossible to seal. I have not replaced the cover yet, but have put in several seals. Your JD dealer or one of the GTT sponsors will have the seal or at least can order from JD.
Yep, left sitting on the seat. Same with mine; just enough to make it messy.Don,
My 425 has just over 720 hours. If you mean left as you are sitting in the seat that is the same side where mine is leaking. I wonder if it is some manufacturing quirk. It seems like there is just enough oil that leaks every 1 1/2 hours of operation to attract dust. It never show on the dip stick! Thanks for the info on the packing. I'll check with my dealer.