You will of course have to remove the gauge which is held on by 4-nuts. Here is a picture to help with location (they require an orangutan or patience).
https://www.flickr.com/photos/advance-design_parts_co/8128963514/in/set-72157631866985745You need to pull the light sockets (push-in).
You need to undo the wiring (disconnect the battery, or enjoy the light show).
Next you need to undo the small oil line (plug it with tape so it does not leak).
Then the tricky one, the coolant sensor. It is located on the head and cannot be removed from the back of the gauge. If you damage it or it gets folded or cut you will need a new one. Remove it from the head and when you pull the cluster from the dash take the entire tube and bulb with it. You will need to push the dash grommet in to do this. If original you will have to use a razor knife to carefully slit the grommet. It should look like this if you have done it correctly.
https://www.flickr.com/photos/advance-design_parts_co/8129487605/in/set-72157631868452754Now the easy part the chrome bezel is crimped to the gauge body in 4-spots. Here you can see the crimped area on a 54' speedo.
https://www.flickr.com/photos/advance-design_parts_co/12181601465/in/set-72157631868452754Using a small screwdriver pry them up, it only goes on or off one way. Replace the glass using a new gasket (may want to consider new decals depending on condition). Here is a Tech Tip that will help as well.
http://www.stovebolt.com/techtips/interior/gauge%20cluster/index.htmlReassemble and reinstall, welcome to one of the hardest jobs on the truck, removing gauges. Good luck, if I missed a step (swear jar, no children in area, etc.) someone else will chime in.
