I looked at your first picture and thought that the chain would un-wind but the third picture shows you changed it.Im a strong paratrooper, but I thought it best to use my engine crane to lower the bumber.
I also found most of the new fasteners I will need, all grade 8. i ordered the lock washers too.
And heres a picture of my "power tool", its an oldie, and I think it was used to fix WW1 tanks !
Keep up the good work. Don't drop the winch on your toe.