Hello, I am in need of some help with my 2650. I have spent the last few months tearing it apart and unlocking the gears that had the right rear wheel jammed. Putting it back together now I wonder how much gear oil to put in the gearbox. And should I just use 80w90 or something thinner? I am in southern Ontario Canada and use this machine for snow removal. Any help would be much appreciated. Please and thank you.