'81 model year R65's were the worst year for valve recession, my '81 had to have valve and seats replaced at around 45,000 miles .
Has a transmission input spline lube been done, if not there's an expensive repair lurking, if the splines are worn .
If it still has OEM brake lines, they are in need of replacement .
Look at where the brake handle goes into the master cylinder, not uncommon to fluid fluid there, due to corroded master cylinder bore .
Oil under the transmission on the engine case, may be the early signs of a rear main seal leaking .
Gear oil dripping out of the neutral switch is common, a pain to replace while the transmission is still installed .
Gear oil dripping out of the gap between the rear wheel and final drive, most likely brake camshaft o-rings leaking, could have oil contaminated rear brake shoes .
Do the rear shocks still have small adjustment handles, if they do, they are original, the shocks were not that great when they were new .