Hey guys, I just purchased a Sears Lawn Spader,, tiller. It is an older model with the 8 HP Briggs engine and the High/ Low/ Reverse gearbox. I am wondering what type of gear oil to use in the transmission, and how much should be in there. My first instinct is to fill it up until it comes out the filler plug,, but that seems like too much... is someone familiar with this equipment?