This is for hydraulic fluid for the power steering. My 2005 Bounder has a label stating to use Dexron III. Flush it out ASAP before it ruins your PS pump.
2005 Bounder 34M, Freightliner XC Chassis,
7.2L 300 HP Cat C7, Allison 3000MH 6 Speed
2017 F-150, Blue Ox Avail, M&G Braking System