The filter was completely clogged with metal shavings. Reusable metal filter so cleaned it out in parts washer and 3 point happy now. I don't know the history of the tractor. By the amount of metal in the oil it either had a serious bearing failure or is about to. Nothing makes odd noises but something is or has been chewing up the metal. Time will tell.
Thanks for the pointer. Expected something serious since it just quit working and wasn't a gradual issue.