I made a mistake in thinking this model tractor has 3 ranges, H, M, L, BUT the OP corrected me; It only has High and Low range.:duh:
I apologize for my error in the original, unedited post below.
It would seem you could use High range, for tasks like plowing on level grade, however I think it would be more effective to move larger/deeper snow accumulations in Low range. Note on HST tractors it is referred to as ranges instead of gears because the transmission is more of a fluid flow component than a particular selected gear in a manual transmission. The forward or reverse pedal is akin to working the clutch when looking for more or less traction in a particular range/gear respectively.
High gear is NOT for plowing or doing any appreciable work with your tractor. You should use low or medium only, and 4wd for plowing, regardless of level grade. H is for over road travel, medium and low for actual work. 4wd for traction, snow, sand, mud, etc. Differential lock, if equipped, for additional traction, when stuck or nearly stuck, in straight front to back movement, not when turning.
That's the facts, Jack.:thumbsup:*
Refer to red text above.*