X9 Winch fault?

I have a Superwinch X9 Winch. the original which was fitted was stolen whilst at a local land rover workshop whilst having a new chassis fitted. I was given a second hand one they had in as a replacement. got it home and can't get it to work in more than one direction. Even when set to free wheel you can only hear the motor powering in one direction. I have taken the drum off and with the motor free, and with power will run in both directions. It seems to be unable to overpower the drum brake

Anyone have any suggestions before I take it back to the garage.