[tacd44]

If you drive straight on even pavemant, you'll be ok. When you turn, the axle can bind up when it's enguaged. This puts load on u-joints, steering, and the front driveshaft. The front tires need to be able to slip, which they can in dirt.

"All wheel" drive cars have a center differential between the front and rear axle which allows them to turn at different speeds,v which reduces binding.