Well, I got out to the junk yard and removed the first axle. It looked perfect til my son noticed a small sratch in the surface of the axle where the bearing rides. We took out another and the pumpkin was full of water. We removed the axle and it was pitted and starting to wear where the roller bearings ride.
I found one at an on line junkyard and paid $100 delivered. Otherwise I was looking at 40 if I took it out or 60 if I had them do it. Shipping, if needed, was 20 or 25 more. I hope this is the source of my rumbling noise, but it sounded like it was up front, where I have already rebuilt the brakes and bearings.
FYI