On top of the t box on my Chopper it says to check oil every 50 hours. Is this referring to the oil in the t box or the hydro oil resivoir? Is it the same oil? Do I ever need to pull the top off of the t box? If so what do i look for? I am clueless on this topic so please help. BTW I did pull the top off of it about 2 years ago and everything looked fine but then again I didn't know what I was looking for.