94.5 Medalist Rear End Oil

[dyurisich]

Hello fellow gassers, new to the site. Have a 94.5 Medalist gasser with a 4 inch lift that I bought used from a golf course in the Chicago area 3 years ago. I have managed yearly tune ups with no problems, (oil change, spark plugs, gas and air filters) changed the oil filter last year, and put new starter and drive belts on this year.
My question to all of you out there is do you think it necessary to change the rear end oil? I have no idea if it has ever been changed in the 15+ years of its life and I'm thinking it can't hurt to do it.
Also, I think from reading the posts that Ez Go recomends 30W non detergent oil. Should I stay with that oil? Any others for this cart? It's driven from April to November at a campground 60 miles southwest of Chicago in temps from 40* F to 95*F.
Thanks for reading and any comments would be welcomed..