Abstract: A mud saver valve being operable in conjunction with a top drive unit to retain mud in the top drive unit when a tubular is disconnected therefrom. The valve utilizes a spring-loaded piston to control the flow of mud or other fluid onto the work area and environment while the top drive unit is being connected to the new tubular and re-connected to the original tubular string. The valve further comprises multiple check valves for evaluating as well as monitoring wellbore pressure. The valves provides for full bore flow passages for the mud or fluid being pumped into a tubular fluidly connected to the top drive.