For those in the truck and SUV community, especially concerning the 4 Runner, the term AWD can be misleading. While often used interchangeably, Full-Time 4WD is the more accurate description for systems that offer continuous four-wheel drive capability. Essentially, Full-Time 4WD builds upon traditional part-time 4WD systems by incorporating a crucial component: a center differential.
Traditional part-time 4WD systems typically offer modes like Rear-wheel drive (2 High), 4-wheel drive (4 High), and 4-wheel drive with low gear (4 Low). However, lacking a center differential, these systems distribute power evenly between the front and rear axles. This fixed power distribution means the front and rear wheels must rotate at the same speed. Consequently, using 4WD in high-traction situations, like most paved roads, can cause drivetrain binding and potential damage.
Full-Time 4WD systems address this limitation by adding a center differential. This differential allows for power transfer between the front and rear axles and accommodates variations in wheel speed. In “4 High” and “4 Low” modes, the center differential typically locks, mimicking the behavior of a part-time 4WD system in those settings.
One potential drawback often discussed is that “2 High” mode in part-time systems may achieve slightly better fuel economy compared to Full-Time 4WD. Another point to consider for 4 runner enthusiasts is that Toyota doesn’t currently offer the combination of Full-Time 4WD with advanced off-road features like crawl control, Multi-terrain Select (MTS), locking rear differential, and disconnecting front sway bar.
Despite these points, Full-Time 4WD in a 4 runner offers significant advantages, particularly for on-road performance in adverse weather conditions. Part-time 4WD systems are primarily suited for off-road or very low traction scenarios. Full-Time 4WD provides enhanced stability and control in a wider range of driving situations, making it a desirable feature for many 4 runner owners, especially those prioritizing on-road safety and all-weather capability.
