tis a bit worrying :(
ASFAIK it is the original box, I've owned for about 5 yrs, chap before me had it near 10yrs and he never mentioned a replacement.
We did try to get the drop arm off a few weeks ago but due to the fact we could'nt get a hammer close enough to hit it hard we did it in situ..
I do go off road but no where near as aggressive as many I have seen so well withing the trucks capabilities.
So the cause is still a mystery, it would be good to get an expert to look at it but I don't know one :roll:
Hope I don't come across this again 8-[