06 vs 08 Sportsman Speedo

So the cluster on my 08 sportsman 500 hasn’t worked since I got it last year. The speedo and odometer weren’t working, but everything else seemed to work. I just got a cluster from a 06 sportsman 800, and although it looks different (interior design), it works, and the part #s are the same. But now when I click the reverse override it’s not switching through the options. Does the 06′ cluster work differently? I have a reverse override mod, and if I flip the switch it will occassionally change from trip to odo to tach etc.

Also has anyone ever taken apart a cluster and if so how? SInce I have an extra now, i wouldn’t mind trying to take it apart and see if its fixable.