Wheel hop in the rain!

[spannermanager]

I dont think the sound was wheel hop as we normaly think of it, as your description suggests a slippery road and a limited slip diff, its possible it was the diff action causing it. ive come across this with salisbury type diffs ( plate type) i.e ZF, when the lightest wheel 'judders' slightly as it searches for grip, mainly on a high percentage preload, say 75% 'ish...
,it could be the trans movement in which case you need a better front mounting, i had a box moved right forward like yours and used a simple welded in lower strap and removable top part to clamp it solid, a bit like the ones you can buy, no front mounting, it was removed, worked fine for years, hope this helps...