[brian_]

Thanks Brian, I didn't think about the efficiency. I was assuming that power got transferred to the only engaged wheel. I realized that there would be loses in the clutches but thought that would be minimal.

There is no loss when going in a straight line, but a bit of turning means a bit of slipping of one wheel; I had described the most extreme case.

I didn't think about using the same model axle for both front and rear, but that could be done just by reversing the power on one of them I guess.

You don't even need to reverse one, if you use them in the same orientation. If, for instance, the motor is ahead of the axle in the front, it can be ahead of the axle in the back, too.

I won't be towing or offroading the truck but may do some hauling, so yeah durability of the axles was something I probably should have thought about.

Anything involving sustained significant power is a potential concern.

It's not like I wasn't expecting this, but I'll need to rethink my rethinking.

Isn't the design exercise much of the fun?