The best thing that could be done with an D8 of that vintage after being tracked 60 miles (probably with no precautions being taken to monitor final drive temps, oils, etc) would be to turn it into a boat anchor. It's probably all it'll be good for.
When you go into the back end make sure you have a decent-size shovel ready. You'll need it to dig the all the metallic debris out.
I hope you have a large bank account. You're going to need it. Best of luck.
Temps were good pressure was good all the way out there it did sit for a few years before it was ran again and then these problems started.