I have read through about 10000 threads on here dealing with the Polaris AGL. Many are for the 800/900 and everyone has an opinion.

Is there any definitive either way between running ATF vs 75w90 and the reasons behind it?

From everything I have seen people are running both with no issues. The AGL is closer to atf than it is to gear lube. The transmission is "splash lubricated" I believe which to me says that the thick gear oil will cause issues with getting to the gears at the top of the transmission. Does anyone have links to any actual research into the oil? I could not find anything fitting.

What do you run? Which brand and weight? I know this has been asked 1000 times just trying to find any definitive information for the 1k with its combined transmission diff and transfer case in one. Thanks!