Last weekend when it was zero degrees, the speedo stuck at 76mph. It started out from there on my next trip and did it once more. It is now buried past 120mph. I have a 05 duramax lly. I have a juice module, so I know how fast I am going, and the odometer appears to be working okay so I am not too worried, but would like to get it fixed. Anyone else have this issue or know of an easy fix?

Thanks for your help.