Hi Mike,
I found the best way is araldite or a similar 2 pack epoxy resin - works a treat after it has set, although it is non reversible...
I tried hot gun etc previously, which didn't work very well..
I'e seen may people running with both rear diffs locked whilst retaining a decent turning circle, although I've just locked the front diff on my KH for the time being
Cheers,
Adrian