Transmission replacement is a major job requiring professional equipment in most cases. The process involves: lifting and supporting the vehicle, removing exhaust and drivetrain components, disconnecting transmission cooler lines and electrical connectors, supporting and removing the transmission (often 150-400 lbs), installing the replacement unit with proper torque specifications, and programming/adapting the new unit to the vehicle's computer. Used transmissions must be an exact match for your vehicle's engine, drivetrain, and model year.