It seems there's a known problem with GM transfer boxes which wears a hole in the casing. In the US there's a company calledMerchant Automotive who sell a modified transfer pump to upgrade the stock OEM pump housing. See this video https://www.youtube.com/watch?v=Nj5ZS8wOmNk
So just to get my head around this, the transfer box wears it self out by rattling loads. The video shows a really simple fix if you catch the problem in time. Surly this part would be covered by life time warranty if you still in it. If not surly VX has a responsibility to say its their fault and will help with the cost. If later on the transfer box develops a hole then its got to be faulty product.
GM seem to try and cut corners and i seems to bit them in the backside.
How do you know your transfer box is on the blink as you could say?