Drivetrain Overview

The drivetrain is everything between the transmission output and the wheels. Its job is to take the rotational force the transmission produces and deliver it to the tires so the vehicle actually moves. Depending on whether the vehicle is front wheel drive, rear wheel drive, all wheel drive, or four wheel drive, the drivetrain components are different — but the purpose is always the same. Get power to the ground.

The engine and transmission sit sideways in the engine compartment. The transmission output drives two half shafts — also called CV axles — that connect directly to the front wheels through constant velocity joints. No driveshaft. No rear differential. Fewer components, lighter weight, better fuel economy. The front wheels do everything — they steer, they drive, and they handle most of the braking. That is a lot of work for two wheels.

The engine sits front to back. The transmission connects to a driveshaft that runs underneath the vehicle to a rear differential. The differential splits power to two rear half shafts that drive the rear wheels. The front wheels handle steering only. RWD gives better weight distribution and can handle higher power levels than FWD because the load transfers rearward during acceleration — right onto the drive wheels.

AWD systems distribute power to all four wheels continuously through a center differential or transfer case. Most AWD systems are automatic — the driver does not need to do anything. 4WD systems use a transfer case that the driver selects — typically 2H for normal driving, 4H for slippery conditions, and 4L for extreme low speed situations like deep mud or steep grades. Never engage 4H or 4L on dry pavement unless the system is designed for it. Binding and drivetrain damage result from all four wheels being locked together on a surface that does not allow tire slip.