my local farm store has Mystik Multi - Purpose Automatic Transmission Fluid available in 5gal buckets.If the manual says that the oil is 100% compatible & mixable with Donax TG (that meets Dexron III specification) then IMHO any oil meeting Dexron III should be acceptable to use in the system. The spec sheet for Donax TG stating it meets Dexron III is attached.
FYI Chevron Rykon MV has now been replaced by the Chevron Rando range of oils......
i was just about to buy the mystik atf at my local farm store. the viscosity specs are very close to the shell donax tg that genie recommends also. cost for a 5gal is around $60.I researched the same thing a couple of years ago. My Genie (2002) originally came with Dexron but there was a Genie bulletin in the early 2000’s saying they were shipping new lifts with Chevron Rykon oil. I couldn’t find the Rykon locally and I wanted to use a multi viscosity hydraulic oil to refill the system after I refurbished the lift. I used Mobil DTE 10 Excel 32, 5 gallon bucket, Graingers.
I'll only say one thing - good quality oil & filters are the best and cheapest insurance policy you will EVER buy for a machine.
Try to cut corners and it'll often bite you in the a$$.
Right now I'm working on an oil project for a fleet of 37 trucks where a rear axle oil fill costs $1600 a time and we do it 3 times per truck per year.............and you're worried about $500 worth of oil.