The Transfer Case was dry!

I'm only guessing, but I think in 2WD, the drive is straight though, so the lack of oil is probably not that much of an issue, but could it explain why a few weeks ago at Levuka (a week after 5 inches of rain), my 4 speed auto could not put enough power to the ground up a slippery, muddy hill to turn or spin the swampers?
Hmm. I wonder what damage that did to the auto which was reconditioned by the same mob in March?
Any thoughts/feedback appreciated. What appraoch should I take when I front the repairer?