The spring tensioning bolt on the top of the plow is designed to trip the blade when you hit an object, so the blade doesn't get damaged, and whatever you hit isn't damaged also. If the blade is tripping with a load of snow in front of it, then you need to tighten the bolt, so the spring is under more tension. Generally speaking, when I was in the truck equipment business, we set the tension on the plows and told the owners not to readjust it. Some didn't listen and made the plows so stiff that when they did hit something, the blade didn't trip, but the angle cylinders would bend or the ends would break off. If you know that there is nothing in the paved driveway that could cause the blade to trip, then you could leave it in the locked position, however, I prefer to see them in the trip mode. Should you want to pile the snow higher by lifting the blade as you come to the end of the run, and it is tripping too easily, just give the bolt a slight tweak, or return it to the locked position. It is quick if you have the original parts. Pull the hairpin, remove the pin, and the lock and install it in the lower hole. That is why there are upper and lower holes. Never use the plow in the locked position when plowing unknown territory. You run the risk of bending a loader arm or some other part of the loader that wasn't designed to withstand a shock to it.