Went to drain the rear diff on a 450 that has been sitting for awhile. No fluid to drain only a few globs of what looks like grease. When I go yo fill with fresh gear oil it just drains right back out no matter how slow I try to fill. The front diff was no problem. Any suggestions? Could something internal be out clocking the fill hole? The rear end turns fine and I can move the bike around. Just the squeaking noise from lack of fluid. Any help is appreciated. 🙂