Yeah - wouldn't expect the centre diff to last very long - but still would have thought that I'd be able to push it out of the shed even with different ratios.
Something that I noticed tonight - I wasn't able to turn the left front wheel with the car in neutral and the wheel jacked off the ground. It would just turn through a few (5 or 10) degrees as the back lash in the system was taken up. I would have expected the rotation to run through the front diff, then through the centre dif, and then through the gb input shaft, allowing the wheel to spin.
Any other ideas?