A transfer case is a device that distributes engine power, sending power to the rear axle or simultaneously to both the front and rear axles. It's essentially a component of a four-wheel drive vehicle. With the development of four-wheel drive technology, transfer cases have continuously evolved, resulting in diverse styles to suit different needs in four-wheel drive vehicles.
The development of transfer cases has undergone five generations of evolution: The first generation was basically a separate structure with spur gear transmission, dual shift shaft operation, and a cast iron housing; the second generation, while also a separate structure, switched to full bevel gear transmission, single shift shaft operation, and an all-aluminum construction; the third generation added a synchronizer, allowing shifting while driving; the fourth generation adopted a combined structure with planetary gears and chain drive; the fifth generation uses die-cast aluminum alloy, with gear chain drive output, and its low-range gears utilize a planetary helical gear mechanism.
