When I use my tiller, and it has a slip clutch, gets in hard dirt. When I use my rotary cutter, it has a shear bolt, in heavy fescue. I can hear the engine pull down. Then the 3 point hitch will not go down, up works fine.
The first time it happened, I was tilling and the slip clutch did not slip (it had been a while since I used it and it was stuck together) and the tractor almost died when I hit a root. I got it out of the root, raised it up and it would not go back down.