The gear box takes the circular motion from the steering wheel and translates it into a push-and-pull motion that turns the wheels. 

It acts as a lever, multiplying the driver’s effort to provide the necessary turning force, especially at low speeds. 

The output of the steering box, typically through a Pitman arm, connects to the steering linkage that physically moves the wheels. 

In a power steering system, it incorporates hydraulic components to provide the power that reduces the steering effort required from the driver. 

These units are engineered to be a direct replacement for the original equipment, meaning they are built to the exact specifications of the factory part. 

Manufacturers ensure strict quality control, resulting in a durable part designed to meet or exceed OEM standards. 

It’s designed for the specific years and models mentioned: 1986-1989 Toyota 4Runner (all engines) and 1986-1988 Toyota Pickup 4WD models only.