What type of oil goes in a 2010 dyna chain case?

Harley-Davidson recommends their own Formula+ but at around nine bucks a quart you might want to save a few dollars and use a different brand.

I'm currently running automobile ATF in my chaincase and have in the past used everything from plain car motor oil to Harley 20W50motor oil with no problems whatsoever in nearly a quarter-million miles.

The chaincase doesn't have the same requirements as the motor or transmission. Basically all its oil has to do is lube the chain, compensator and two bearings, plus cool the clutch plates. Virtually any oil can do that.

Panheads relied entirely on the oil mist coming from the crankcase breather to lube their primary chain.