Transmission Issues Explained: A Complete Breakdown

How it Works: Transmission

The transmission channels engine or traction-motor power to the drive axle, matching wheel speed to propulsion demands through selectable gear ratios or continuously variable drives. Input torque enters the gearbox via a splined shaft coupled to the crankshaft or electric rotor. In stepped transmissions, synchronized gearsets or planetary carriers engage predetermined ratios: helical gears on parallel shafts in manuals, or epicyclic gear trains in automatics. Hydraulic or electronic actuators relocate collars, clutches, or brakes, locking specific gear elements to reroute power flow and multiply torque. Automatic units integrate a fluid torque converter or wet launch clutch that amplifies low-speed torque and isolates driveline vibration. Dual-clutch gearboxes stage two concentric shafts, enabling lightning-fast, computer-controlled shifts by preselecting the next ratio. Continuously Variable Transmissions employ a steel belt running between adaptive pulleys or a planetary variator to deliver seamless ratio changes, keeping the power source in its most efficient speed band. Dedicated single-speed reducers in battery-electric vehicles mesh spiral gears for compactness and quiet operation. Throughout each architecture, an output differential divides torque between left and right wheels, allowing independent rotation during cornering. Lubrication circuits bathe gears and bearings in temperature-controlled oil, minimizing friction and dissipating heat. Integrated sensors monitor input speed, load, and clutch pressure, feeding control units that coordinate shifting for optimal performance, energy efficiency, and refined drivability across all propulsion technologies in passenger cars, light trucks, and commercial fleets.