drum lock doesn't work on my 5 ton

[sbkarmen]

Hey guys my first thread on here, got my M818 a month ago and having some serious fun on it. the winch was working great and the drum lock was even working. I have it in neutral with the clutch in out and the drum lock engaged but the winch still spins free. If I put the clutch in it will lock. Everything on the winch is still working just won't lock, I've tried to adjust the drum lock screw but no luck does the same thing. any help would be appreciated.

thanks