contact gearboxman bob, he'll tell you everything you need to know.

i can tell you that it's nothing to do with the diffs, but not much more than that. it has something to do with the ratio's in the transfer box i think.

sounds like an interesting project. i would also check with bernie that the diffs will be ok upside down - there may be lubrication issues (like the oil pissing out of the breather hole for a start )