Dyna-Plex 21C® Trac Gard HD may be used in hydraulic systems alone, or in combination hydraulic-transmission systems. It is recommended for most makes of tractors and has been formulated for better performance in axle lubricant applications. Dyna-plex 21C Trac Gard HD is specially formulated to be oxidation and rust resistant. Gears and bearings are protected, even in extreme applications. Its multi-viscosity ensures superior pumpability at low start-up temperatures and provides excellent body at high operating temperatures.