Thank you so much, I discovered the same problem with the same exact wheel today. I'm so glad it's a repairable break as the replacement cost for that axle through DR is $404.00 Again, thank you

If you were to rotate the battery 180 degrees, it would put the positive post further away from the frame. Then there would be less chance of sorting it to ground. However, the chassis is not grounded like a vehicle so there is difference in potential from frame to battery positive. That would also allow you to remove the 2x4. I had to use a shim for my battery on my DR Stump grinder when I ordered a wrong battery... I like my grader and have built my own wireless control that seems to work better than DR's. I had upgraded to their wireless package, but the system failed and I went back to original corded components, but built the wireless system...

A strap over the tube or pieces of angle iron welded on will really support the wheels.

I need to replace the wheel bearings in my father-in-law's unit. Any idea on part numbers?

They redesigned it for a reason. In the lowered position those wheels are dragged along putting enormous pressure on those plates connected to the shaft. Terrible design