Welcome. The brake fluid can be changed by bleeding all the calipers until you get clean fluid to come out. The trans should have a drain plug somewhere on the bottom. Hope this helps.
2007 Sportsman 800 efi , L&R tall windshield, Viper Max 4000 lb. winch with 3/16" Amsteel rope by Atv Winch Rope, 25' Amsteel tow rope by Atv Winch Rope, RDC fairlead, RDC deluxe gas cap, RDC shifter, RDC overflow bottle cap, RDC 2" lift , 27" Maxxis bighorns s/w on Vision Outback 12" wheels, Uni air filter, Dalton o/bl primary clutch spring, front and rear brushguard, front and rear rack extensions, and a SanAngelo backrest