Same kind of thing happen to a couple of owners of ARB bumper owners who winch on 2K’s. Ned being one of the ones I remember, I saw 1st hand what happen...his bolts where torque down properly yet the frame horn holes ended up elongated after a normal pull. He eventually went with the extra bolts on each side like Jim suggested and also welded on a L type bracket on top and did’nt have any problems after that.

When I put my winch on my ARB I just went with the extra bolts on each side and haven’t had any problems but without them the bumper is not secure enough for pulling IMO.

Brian