A drive unit of a top drive system includes a drive stem having a plurality of ports from an exterior thereof to an interior thereof. A plurality of sliding coupling members is disposed in the ports. A coupling collar encircles the drive stem and has actuation surfaces and recessed surfaces on an interior thereof, wherein the recessed surfaces align with the ports when the coupling collar is in a first position, and the actuation surfaces align with the ports when the coupling collar is in a second position.