I have a 2017 Chevy Silverado truck and a new 7' 6" Fisher plow that the two times I have detached plow and tried to reattach the plow is too low to drive into cradling mechanism. I have placed supports under the plow arm to raise it but will not fully engage so pins enter holes in truck attachment bars. Am on level, cement surface but the plow always drops lower than the truck attachment arms. It took some time to finagle the mechanisms the first time and am in the same place again this time.
RWB
Sounds to me like you have 2, possibly 3 problems here.
First, as others suggested, when taking it off, put the plow in float mode, then get out and push down on the lift arm (Triangle thing). This step is paramount.
Second, I don't care what methods you use, the headgear, more often than not, will tilt back some when taking it off, if not when it's just sitting there in between use. This will mess up your alignment some when reattaching. The easiest way to mount it is to have a second person to pull back, or push forward on the headgear to align it with your truck as you drive into it. When solo, simply get as close as you can to the plow without coming into contact with it, and adjust the headgear by pulling it forward, or pushing it backwards to get it at the same height as the push plates on the truck, then gently pull the truck in the rest of the way while watching the headgear closely to make sure it doesn't move while you're getting back behind the wheel and driving into it.
Third, another thing that could be playing a roll here is when you dismount it, you could be at that precarious height where you're not putting the jack stand down enough to hit the right hole. To eliminate that as a possibility, follow these steps everytime:
1. Drop the blade, and put the controller into float mode.
2. Put the truck in park, but do NOT turn it off, then get out of the truck and push down on the lift arm all the way
3. Pull the jack stand release handle. IMPORTANT - IF the jack stand automatically locks into a hole once it hits the floor at this step, this maybe your problem, IF you're doing everything else right, and this is the case, put a 12"X12" piece of plywood, or other spacer under the jack stand first.
4. Go around the front of the plow and push & hold the headgear all the way back towards the truck as far as you can push it, while holding it in that position, pull the release arm for the locking pins, THEN let the headgear go.
5. Disconnect electrical connectors and back out of the plow keeping your wheels straight until you're all the way clear of the plow.