Remove the facia plates on the left and right of the custer, there are 4 screws holding it in the dash, remove them and the wires to pull the cluster out. Make notes of where the wires go.
Remove the screws holding the circuit board on the back. The clock/tach does not have to be taken off the back, it will come out with the board. Do not force anything, if it does not come off easily look for a missed screw.
This was the problem in my case, the car had sat for a couple of months and the gear shown had seized on the shaft. When I drove it again the gear stripped. I had a spare from a junker, so I replaced it and I'm back on the road to 200K.