The story is over, but I hope not the lesson. The pump was installed by the dealer and it still wouldn't work. I just gave up and had the dealer order a new pump. He installed the new pump (plus the hydraulic fluid and filter) for $640. It is like new (he says, I still have to pick it up).
So my efforts to fix the mower ended up costing me $1200 or so instead of just $640.
I do have a spare wheel motor now. But I'm still beating my head over this one. Here is what I think I did wrong:
1. Should have called more than one dealer to get a price estimate on the pump. The dealer I called first quote the full Snapper price of over $800. The dealer I ended up going to got the pump from the OEM for $480.
2. After the pump wasn't fixed the first time, I should have given up and taken it to the dealer (who was recommended by the hydraulic repair place). Instead I took the wheel motor and pump back. Pump worked for them, so must be the wheel motor. Purchased an new wheel motor. Same problem.
3. At least at this point I did take it to the dealer. But maybe I should have hauled the whole mower to the hydraulic shop. Guess I'll never know on that one. But I have no faith in the hydraulic shop now and I really don't think they want to see me again.
Off to spend what money I have left on beer.