Total Loss of Drive...

Off roading at the weekend and lost all drive to all wheels. Centre diff had packed up previously.

Pulled the rear halfshafts out today - All fine. Pulled the diff out and the little gear (is it a planet gear?) on the diff pin was in pieces, so that explains the rears.

Both front and rear props were turning so the gearbox is alright

Got the front to sort out next, them front diffs aint so easy!

I can't drive it without the centre diff working if I have screwed the front up, but is there a scenario where blowing the back diff will cause all drive to stop?

Oh come on....one of you must know!

I drove my classic for months with one prop shaft removed so in short the only way to lose drive to both is two stripped diffs or a knackered centre diff. With permanent 4wd without a viscous centre diff (disco, landcruiser, Gwagen etc) losing drive on one axle for whatever reason will bring the vehicle to a halt until you lock the centre but as far as I know when viscous diffs pack up they go solid rather than allowing free turning so I'd guess that you've stripped the front too.
I'm nearly sure that the rear set up is stronger than the front due to towing and load carrying requirements so whatever caused the rear to go is likely to have done the front too.