Where does odometer get is signal from?

[nitro325is]

I know it has a sensor on the diff which Ive already replaced but I still cant get the odometer to work.I swapped with my brother and it works fine in his so its not the odo gears or anything within the gauge cluster.Do the wires from the diff make any other stops before the cluster?

[Jordan]

If your speedometer works, then a gear is broken inside the tripometer/odometer housing.

[e30evolution]

If your speedometer works, then a gear is broken inside the tripometer/odometer housing.

he said he put his guage cluseter in his brothers car so nothing inside the guage cluster is broken