We just recently bought a John Deere 790 compact tractor and I was going through all the fluids and checking them to make sure they all topped off. I noticed a little dipstick on the front axle of the tractor which I'm guessing is for the front differential fluid. I just would like some help on knowing what kind of oil I use for the front diff. It says on the cap "oil type #90" is that what I use and where is the fill hole to put this stuff? Much help would be appreciated.