A differential will transmit power equally to both wheels until one loses traction then all power goes to the spinning wheel.
An open diff will allow for one wheel to spin faster than the other when cornering.

A locked diff will not allow for different wheel speeds and will chirp around corners depending on the locker.

My 91 Land Cruiser is a full time 4 wheel drive with a differential in the transfer case.
All it takes to stop it is one wheel spinning until I lock the t-case.
If it's icy I chain the front wheels and motor on.

Semi tandem axles are pretty much the same thing, both axles are driven and all 4 wheels get power till one slips then you lock the front axle power divider. If the diffs have lockers then you can lock the whole deal up.