The parking lot was so icy I could just about stand , so no I did not really pull hard like you said.
I did not try to pull the cable out with the pto engaged , due to the fact that it felt like if I'd unhooked the cable from the pole it would have just pulled the cable in .
It may just need to be used so the clutch releases properly.
Some people are over lubricate the drive chain and oil gets to the clutch so it sticks and slips under load.