VE SSv A6 2012 Diff Change 2.92 to 3.45 now Speedo incorrect

[UjisCaprice]

Just got a 3.27 installed and speedo didn't change. 2007 v8 caprice

 

[Gerardop]

I just changed the diff in my VE Ss and the speedo is out by 20 - 30km at higher speed. When I plug into OBD the computer reads the correct speed while the display is shown much faster. Any way I can fix this myself?