How do you get into 4 lo?

To get into 4 LO on your transfercase, you first need to bring the vehicle to a complete stop, and shift your transmission into neutral. THIS IS VERY IMPORTANT!! Now you can shift into 4 LO. The reason you need to do both is simple, you are about to change gears in your trasfercase so you need all the gears inside to be completely stopped. The transmission will turn the input shaft in any gear except "Neutral" or "Park". And the wheels will always turn the output shaft, unless they are stopped. If anything is moving you will grind the gears in the trasfercase.