What are Full-Time 4WD and On-Demand 4WD?

[James]

Full-Time 4WD and On-Demand 4WD are explained as follows: 1. Full-Time 4WD: Full-Time 4WD means that the vehicle is always powered by all four wheels independently. It achieves this through a flexibly connected center differential, which then distributes driving force to all four tires via independent front and rear axle differentials. Unlike purely mechanical differential locks, Full-Time 4WD differentials can be either viscous coupling or multi-plate clutch types, but both allow for speed differences between front/rear and left/right wheels. Whether a vehicle has Full-Time 4WD depends entirely on the transfer case design. As the core component managing different drive modes, the transfer case significantly influences overall vehicle performance. 2. On-Demand 4WD: On-Demand 4WD automatically switches to four-wheel drive only when necessary, otherwise operating in two-wheel drive. The system automatically shifts between 2WD and 4WD modes based on road conditions without driver intervention. This differs from Part-Time 4WD which requires manual switching, and Full-Time 4WD which always powers all four wheels.