2005 6.0 F350 dually, speedometer quit working and the ABS light came on. I replaced the speedo sensor in the diff, but to no avail. Hear a lot about the cluster, however nothing with the ABS light on.

 

Not saying it's right but it's all I could come up with.

 

The first step is to check for DTCs before replacing part(s). Since this particular vehicle obtains vehicle speed information networked from the ABS module, a logical first step along with checking for DTCs on the ABS module would be to verify B+ and B- getting to the ABS module in the first place.

 

THIS