The Truth About 4WD Lock That Most People Get Wrong..

A lot of people assume that when you put a truck into 4WD Lock, all four wheels are going to spin at the same time. But that’s actually not how most four-wheel-drive systems work. In this video, I demonstrate it using my own Ram 2500 Power Wagon on ice. With the truck in 4WD Lock and both differentials open, only two wheels actually spin — one on the front axle and one on the rear. This surprises a lot of people, but mechanically it makes perfect sense. 4WD Lock simply locks the front driveshaft and rear driveshaft together so both axles receive power. But once that power reaches the axles, the differentials still determine which wheel on each axle spins. An open differential will always send power to the wheel with the least resistance, which is why you often see just two wheels spinning in low-traction situations. That’s also why features like limited-slip differentials and locking differentials make such a big difference off-road. They change how power is distributed at the axle, not just between the front and rear. In this demonstration, I leave the lockers disengaged so you can clearly see what’s happening mechanically and understand how the system actually works in the real world. Understanding this stuff really helps when you’re driving off-road or in winter conditions, because traction isn’t just about having four-wheel drive — it’s about how power is managed all the way to the tires. Curious what you think — did this surprise you, or is this something you already knew? Let me know in the comments.