Dump it out. ‘Fine’ filing is normal. Chunky stuff is a prOblem. Pull the plug on the side and re-full till it is level with the plug. Lots use skidoo oil but 75w90, atf, 5w30 motor oil will also work just fine. Have logged over 2500km on each without problems
Mine has had nothing but ATF since day 1, changed the chain for preventative maintenance at 4K. Holds 8.5-9oz... Just over 250ml. Transfer case on a truck that holds way more hp is oil bathed via atf....
also make sure the rubber gasket (washer) behind the tensioner nut is in good shape.
ATF is thin, and like stated above, is put into transfer cases of diesel pickups with people doing 800+ horsepower boosted 4wd launches at the track all day long.
Chain tension finger tight on the tension bolt, back 1/4 turn, lock up the jam nut when holding the tension bolt.