Transmissions have a number of different parts, which may include the clutch(es), intermediate shaft, differential, and/or torque converter depending on the type. Any one of these parts could fail, which would have an impact on the transmission and the cars overall performance. These failures could be caused by a number of different factors. A person’s driving style could cause wear or damage on the parts, a collision with an object or something thrown up from the road surface could also cause damage. However, all of a transmission’s parts wear naturally over time, and failure could simply be attributed to natural usage.