My W460 has no center differential, thus when the transfer case is in 4WD and the front and rear differentials are locked, then any there is no speed differentiation between front and rear axles. Thus, even if only 1 tire has traction, you can still move.
Did I get that right?
when your transfer case is in either 4WD Hi or 4WD Lo there is no speed differentiation between front and rear axle (both drive shafts are forced to rotate at the same speed)
left and right wheels on each axle are still abel to rotate at individual speeds
only when you lock your axle differentials, the wheels as well are forced to rotate at one speed.
In theory, with all lockers on, you could still move with traction at only one wheel.
If the amount of traction of one wheel would be sufficient to move a car under most circumstances, we could simply produce 1WD cars.
There is a reason why we invented 4WD.
To have more traction as counter force for the torque needed to move heavy cars in uneven terrain.
In some very rare cases one wheel might indeed produce enough traction to counteract the torque needed to move the car (extreme grip plus a good amount of weight). However, in that case maximum torque generated by the truck is acting on only one axle shaft - quadrupling the force on that one axle shaft. If all 4 were on the ground, each would carry 25% of the torque.
If you are not super gentle with your gas foot, you'll break that axle shaft, or the CV, or the spiders in the diff.
The strength of the G provides some protection, but it's not unlimited.
Your 300GD produces roughly 340 lb/ft. First gear roughly 4:1, transfer case 2.14:1, axles 4.9:1 = 42:1 crawl ratio.
42 x 340 = 14,280 lb/ft in low range, first gear.
So, 14,280 lb/ft would be the force acting on one axle shaft, if you had (sufficient) traction on only one wheel.
Quite a lot. And thus better spread out over all 4 wheels (3,570 lb/ft ea).
nuff for now