4x4 Transfer Box Breaking

[scooper1]

I have a 1999 mk1 4x4 which has now destroyed two transfer boxes - second one from a known good car lasted 8 miles

box is actually cracked in half and second time was repeat of first

all mounts and shafts seams ok

gearbox is not lose

 

it looks just like the gearbox is being supported by the transfer box and that it gives up and cracks from the stress of supporting the gear box but the gearbox mounts and fixings seam fine and seams to be firmly mounted to engine. The transfer box also has a bracket to the engine . Transfer box breaks in half between this bracket and the gearbox mount

 

the car has only done 40,000 and it now looks like i going to have to scrape it

 

The only thing I can think of is that the autobox is locking up and putting all the stress on the transfer box - Has anyone heard of this on the AG4 gearbox