Christopher beat me to it! I was going to say the same thing. 2 screws on the bottom edge and clips at the top.
1. Check all connections at the back. Even pop them off and clean them with some electrical contact cleaner.
2. Check the DIP switches. My tach was weird because the DIP switches were improperly set. I also lost my speedometer at one point because I had insecurely mounted the dash cluster and a DIP switch was accidentally thrown.
Here's my related post: http://www.skoolie.net/forums/f27/ar...tml#post150864
And Cadillackid's post that helped me fix the problem: http://www.skoolie.net/forums/f11/th...tml#post150821
3. Could be a loose wire somewhere. If you know how to use a multimeter you can probe around. Sometime back I posted a diagnostic manual for my International with the T444e. Here's the link: https://www.dropbox.com/s/y1vt3i3ude...0optimized.pdf
. You have a different engine, but the colour codes for the wires coming out of the dash are likely the same.
4. It could be that the circuit board is self destructing. There are some repair services available on eBay that can check it over and fix it for around $130. Here's one I found with a quick search (note that I've haven't used any of these services): International Truck Speedometer Cluster Repair Service TO Your Unit | eBay