Which 4WD/AWD system cannot be operated on dry pavement when engaged?

Part-time 4WD systems are specifically designed to be used in off-road or low-traction conditions. When these systems are engaged, they typically lock the front and rear axles together, causing both sets of wheels to turn at the same rate. This setup is advantageous in slippery environments, such as mud or snow, where maximum traction is needed. However, when driving on dry pavement, the differences in tire rotation speeds during cornering can lead to excessive tire wear and potential damage to the drivetrain, as the wheels will not slip to accommodate for turns.

In contrast, full-time 4WD systems are designed for all-weather use and allow for a degree of slip between the front and rear axles, making them suitable for operation on dry pavement. On-demand 4WD can switch between two-wheel drive and four-wheel drive based on traction needs, allowing for safe usage on dry roads. Front-wheel drive (FWD) systems operate solely with the front wheels and do not engage four-wheel drive mechanics at all, avoiding the issues associated with part-time 4WD systems on dry surfaces.

Thus, part-time 4WD is the system that cannot be operated on dry pavement without risking drivetrain damage or increased tire wear.