Transfer cases are compatible with various four-wheel drive systems, including part-time, full-time, and on-demand four-wheel drive. Traditional transfer cases employ a purely mechanical structure, switching between two-wheel and four-wheel drive via 2H, 4H, N, and 4L gears. In 4H mode, the rigid connection between the front and rear axles maintains a 50:50 power distribution, while the 4L gear enhances torque output through a high-ratio gear, suitable for hardcore off-road scenarios. Super Select transfer cases feature a central differential, supporting 4H mode on-road four-wheel drive. With 4HLC/4LLC modes, the central differential lock can be engaged, combining full-time four-wheel drive and off-road capabilities.
Super Select 4WD systems have evolved from the first-generation mechanical structure/viscous coupling to the second-generation electronically controlled multi-plate clutch structure, enabling free proportional torque distribution between the front and rear axles. Transfer case technology continues to develop, with companies such as Great Wall Motors and Beiqi Foton obtaining related patents. Some companies have also raised funds for projects such as wet friction plates for transfer cases. Major transfer case manufacturers include BorgWarner and ZF.
