thanks for the reply,
I am a certified KY redneck, so I went another way,
I leveled the cutter, then took both upper and lower fill/drain plugs out, then started tractor and let it idle with cutter running,
this action pumped the oil out of the lower hole, am sure I did not get all the oil out, but enough for me. I refilled the gearbox to the proper level with 90 weight gear oil.
I plan to run the cutter for a few hours then drain the gearbox again using the same method, that should get 80%+ of the old oil out of the gearbox.
time will tell if it works, if not and the gearbox starts leaking, it will get lubed with john deere or caseIH cornhead grease.