Please help ASAP

I'd blow compressed air into the 'splines', then any kind of thin oil. If you heat the other end, the oil will migrate to the heat. While that's weeping in, get a hold of Woods and get a diagram of the unit. It'll SHOW you how it's all connected. Odds are it's been on since day one and has wedged itself tight. If you can lightly turn/whack it opposite direction, add more oil/heat... it should slide off. May need a puller or 2 screwdrivers, opposite side may work...BTDT.
Jay

Its just rust. your bolt lined up with the groove in the shaft. penetrating oil and heat and possibly a puller or two pry sticks are your best options. Good luck !