A specific type of drivetrain component involves a gear-driven unit that transmits power from the transmission to the axles, enabling four-wheel drive capability. This unit is mounted separately from the transmission, connected by a driveshaft. An example application of this setup can be found in certain older trucks and off-road vehicles where design constraints or specific performance characteristics necessitated this configuration.
This configuration offers several advantages, including increased flexibility in vehicle design, allowing for greater wheelbase variations and easier adaptation to different chassis configurations. It also simplifies maintenance and repair, as the unit can be removed and serviced independently of the transmission. Historically, this design was prevalent in vehicles requiring robust and reliable four-wheel drive systems, contributing to their durability and longevity in demanding environments.