I'd stick with the Demand Drive hub fluid,but you do have other choices on the gear oil and plenty on the motor oils.Haven't kept up with Polaris prices,but here's one that's about 9 bucks. Maybe more out there that's cheaper.

 

I will look into that, will it replace both the transmission and rear diff fluids? I already use mobile one full synthetic for the engine oil.

 

On machines such as the Magnums and Sportsman 700 and 800s that have separate rear diffs I'd still use a thicker lube as recommended since they have ring and pinion gears. You don't have to us Polaris Angle Drive fluid. 75/90 or 80/90 GL4 or GL5 is ok and really the same lube as the Polaris brand. It's also recommended on the older front diffs also with the awd in the hubs. This lube you can get anywhere in different brands at a lot cheaper price.