zak99b5
Full Access Members
If it's like my 2010 Suburban system, 4WH locks the transfer case. Need to be on slippery surfaces, or the drivetrain will jerk and bind. On 4WAuto, a clutch in the transfer case allows the fronts to engage/disengage as needed, so there's no binding. So it's fine to use in all road conditions. But I use 2WH to use the clutch in the transfer case as little as possible and save a little gas.