Pull the cluster out until you feel the tension of the speedometer cable.
Normally, there will be just barely enough room for you to get your hand behind the cluster. You will need to feel around the center of the cluster, behind and to the right of the center of the speedometer cable, for the connection for the speedometer cable.
The cable screws on to the back of the cluster with a knurled knob. It is to be loosened by hand. No tools will be necessary to unscrew this. Unscrew the cable until it is free of the cluster.