What is a driveshaft/what does it do?
A driveshaft is responsible for transferring power from the engine, gearbox and differential to each driven wheel of the vehicle.
Getting into the details of driveshafts
For front wheel drive cars there are usually 2 driveshafts, 1 per front wheel. They link the central differential to each wheel hub, causing it to rotate when the cars gears are engaged, in turn driving the wheels.
For rear wheel drive cars, power from the engine and gearbox is transferred via a prop shaft which runs down the centre of the vehicle to the rear axle and the rear differential. From the rear differential power is transferred to each of the rear wheels via driveshafts. As with a front wheel drive car they are connected to the wheel hubs causing them to rotate, driving the wheels.
Four wheel drive cars have a combination of both setups with driveshafts running to each of the 4 wheels.
In some cases drive to the rear wheels is housed within a sealed axle unit containing the rear differential and 2 driveshafts, referred to as half shafts.
However, most modern vehicles have exposed driveshafts with universal or constant velocity (CV) joints at each end. These joints connect the driveshaft to the differential and wheel hub and allow movement through either suspension or steering.
What if something goes wrong with the driveshaft?
A driveshaft is a not usually prone to fail as it’s typically made of thick walled steel with no moving parts. However, it could be damaged due to impact with stones/rocks or other debris causing it to be imbalanced, which would cause vibration when driving. More common is wear or failure of the CV joints at either end of the shaft.