Transmission replacement involves removing a vehicle's old transmission and installing a new or rebuilt one. The transmission is a crucial component that helps transfer power from the engine to the wheels, allowing the vehicle to move. Signs that a transmission may need replacement include slipping gears, unusual noises, or fluid leaks. The process typically requires specialized tools and knowledge, making it essential to have a qualified mechanic perform the replacement. Depending on the vehicle's make and model, the cost and time for transmission replacement can vary significantly. Regular maintenance can help extend the life of the transmission and prevent the need for replacement.