Hi Dave, sorry I was not around when you had this trouble.
I run 35 front 33 rear, this measures ok using Earls method. The VTD center diff is still effected by differences in rotation. The diff has a clutch that operates across the diff to lock it up, if the rotational difference is too much, like when front or rear wheels spin. Under normal conditions the sun and planet gears rotate as a solid unit, it is only when there is a difference, that the planetary gears run.
A small difference front to back won't worry it, but to have the trouble that you had, the car would have to have the front wheels lifted and be towed on the back wheels.
When the transmission is in park the front wheels are locked, the back wheels are not, so when it is towed on the back wheels, they drive the transmission output shaft, through the planetary gears. Thats why it was destroyed, it wasn't miss matched tyres that did this.
I might be going out on a limb here, but there can be no doubt that this was done between WA and Q,LAND. Somewhere they did a front lift, towed it at 60kph for long enough, to destroy the gearset.
Harvey.
