With the hydrostatic transmission, this is REAL easy. Simply rock the treadle back and forth a little, and the Dif-Lock will engage, assuming you put your left heel on the pedal. I do it all the time to avoid digging holes by spinning the back tires. You can let go of it while moving, and it won't matter. I work more in 2WD than I do in 4WD, simply because it's easier to steer the tractor, and less stress on the drive-train. As good as the match is, 4WD demands that the front wheels move exactly the right RPM to keep up with the back wheels, Pi*D, and all that. They don't, I assure you. The math is close, but not exact. The gear ratio between front and rear as perfect as it will ever be while your tractor and the tires are new. The gear ratio should remain fairly close, though, and definitely close enough for the intermittent 4x4 requirements on dirt/mud/ice.