Last winter, I used a piece of wire coat hanger to check the condition of the gear lube in my snow blowers gear box. What I found was that the oil had turned grey. I was thinking that the gears were shot, or a bad bearing, but figured that I would get to fixing it in the warmer weather. Totally forgot about it till today, and decided that it might be best to just drain and refill the gear box. The drain plug takes a 3/16" Allen wrench, and a very long piece of 3/8" iron pipe to get it loose. I think that it was installed with Locktite at the factory. Once I got the plug out, I rolled the blower forward to allow all the gear lube to drain out. I used the cut off bottom of a 2 liter plastic soda bottle. To my surprise, what came out was a lot of water, and then the black gear lube. Being a closed system, you don't think about changing gear lube very often. I refilled it with 80/90 gear lube, and after the next time that I use it, and the gear lube is hot, I will drain it again, and refill. I am relatively certain that there is still some water in there, so the second change should take care of that. To get the vent plug out, you need a 3/8" box wrench, preferably a 6 point. Don't gamble your gearbox to water damage, because a new one is very expensive.