Just did that on a 1460. Cost me about $175 at the dealer and it still leaks. I don't know what the answer is, I guess just keep pouring hy-tran to it on a regular basis.
Same with me on a 1680. We tried, then let the dealer try, and no luck either way. Just a oil spot on the front tires in the morning and alot of dust stuck everywhere.
Maybe this will help or maybe not as it worked in stopping an oil leak between valves in an IHC tractor but is not from a combine.Put in new O rings and leak was still there.Put in new bolts and there was no leak at all so figured the bolts had stretched or weakened enough to allow leakage.
Butch, most times it isnt the orings between the valves. All the plugs have orings under them that need replaced and there are small allen screws with tiny orings on them that are the problem alot of the time. When you take the valve stack off replace every oring that can leak to the outside. There is no reason to have that oil spot on the tire. Good luck.