I thought about this one on the highway today. Which wheels on the tractor of an 18 wheeler are powered by the engine? Are both sets of rear wheels powered, or just one set? It seems like it would be rather difficult to deliver power to two separate axles, one behind the other, as opposed to just one of two.
The majority of big rigs you'll see on the highway are putting power to all the back wheels, but not the front two. Some exceptions are heavy duty logging trucks and other speciality trucks that need a diff locking system for harsh terrain or crazy maneuvering though areas that are hard to get to, some rigs have all wheel steering for that as well.
I have a little background in gearing from engineering school, but we never got that far into vehicles. We looked mainly at standard trannies and spent a day on planetary gears and differentials, lol. Thanks for the info!
Sure, no problem!