I have a 14c motor grader that I need to change fluids on. I am assuming that the hydraulic tank takes a 30 wt hydraulic oil? What do the gear boxes for the lift, center shift, wheel lean, ect... take, 90wt? I have a parts book but I can't find any specifications chart showing the fluids in it. Also if there are any other tips that any the experienced operators of this vintage of machine can tell me as far as general preventative maintenance is concerned I would greatly appreciate it.