Update. I went went back out and check the level again, and it was way down. So if filled it up with the mobil1 and jacked it up and tied the foot pedal down. A few minutes later I checked the level again, and it was down again. I repeated this for about 1qt of oil. lol
Somewhere along the line, the wheels started turning. Faster and faster. But they'd stop if you laid your hand on it.
A funny thing about that neutral lever, every time I engaged the tranny pedal, it would pop out just a little bit. No more than 1/4". While keeping an eye on the oil level, I'd push and pulled it in and out. (killing time). Well, one time I pulled it out and pushed it in, suddenly both tires kicked in and started turning. I put my hand on one to see if it I could stop it. And it was in gear and not even slowing down. Mowed the rest of the front yard.
So tomorrow, I'll go to the JD place and pick up their brand of hydrostat oil and change out the whole thing.