I have a 3720 with a 59" front snowblower. The snowblower's A-frame is mounted to the front quick hitch with a threaded retaining rod, retaining plate and large wing nut on top. On the bottom is a lynch pin and cotter pin. I presume this arrangement is meant to allow for quick removal but I keep the snowblower mounted throughout the winter.
I find the top wing nut is frequently becoming loose and I'm continuously tightening it down by hand. After using the snowblower today, I returned the tractor to the barn and stumbled across the lower lynch pin laying in the driveway. The end of the pin was bent down and in the closed (locked) position. It's lucky I found this before the snow blower came off the front hitch (maybe the cotter pin is the last line of defense).
This seems like an inferior design and I'm considering replacing the wing nut with a traditional nut I can tighten down with a wrench. Perhaps blue thread locker is another option. Has anyone else had this issue and made a modification?