Bob,
Having had to deal with something similar on my landing jacks on my 5er, look to see if there are some screws on the end where the wrench connects to.
As old biscuit mention, there is probably a shear pin that failed, and you'll need to replace it.
One thing you could check is for lubrication. While these are supposed to be sealed units, I've found my units to be under lubricated from teh factory and required a major disassembly and cleaning before I put marine bearing grease back into the units (which work very well now). If you find your grease has dried out, you're going to need to go through it from end to end in order to insure that you repeat this process again.
I'd start with just looking to see what's there.
FYI, if you remove the entire unit, make sure you measure where everything is before you reassemble the unit and reinstall it. Otherwise, it'll make things a bit more difficult to realign.
