I use diesel fuel or kerosene to flush out the differentials,drain them first ,put the plug back in,fill it with kerosene,then drian again.Keep doing this until it comes clean.Brake shoes aren't hard to replace,Sometimes tricky getting the drum off but once that is off it's not hard to figure out.I just buy shoes from the dealer,usually around $25-$30. I think all years of Foreman 450's were the same body plastics.