Well, finally picked up my tractor yesterday after 5 weeks in the shop. They ended up replacing the hydro pump after the seal replacement did not stop the leak. By the way, my dealer said the warranty records showed that this tractor had already had the o-rings replaced two previous times, and he found some silicone around a couple of screws when he removed the pump. I guess I got really lucky having the remainder of the factory warranty when I bought this tractor, cause he said the pump alone would have been about $1900, not counting labor. I guess I know now why this tractor was traded in.
Highbeam, I never did really find out how much the seal job would have been by itself.