Shell Rotella T6 5W40 in the engine. I run it in my mower, car, tractors, loader, sleds, and trucks too.

I run the same Amsoil Chaincase oil in the transmission as I use in my sleds because I already have it. It's not cheaper than the Polaris oil but I don't have to buy two different oils... The 500HO doesn't have a rear diff. It has more in common with the transfer case in your pickup than a transmission. I've read about people using synthetic 30W or 5W30 motor oils, Pennzoil Synchromesh manual transmission oil, and ATF that claims to be Dexron III equivalent. They may work just fine but I haven't used em. The only ones that have close to the same anti-foaming additives as the chaincase oils are the transmission oils.

Traveler UTF hydraulic oil in the Hilliard front diff. Meets the Hilliard approved John Deere HyGard J20D. I use it in the loader and tractor too. A 2 gallon jug is $19 at Tractor supply and I can get it in 5 gallon pails too.

 

I also use Synthetic snowmobile chain case oil in the tranny since that is what is inside of the tranny ,just one big chain just like in a sled's chain case.