Road speed communicatio error, volvo truck.

I Have a 2008 Volvo truck vnl, with a Cummins Engine. My speedometer isn't working. The codes I've got are eng code road speed data erratic, and instrument cluster fault, road speed communication error. I've checked the vehicle ecu, eng ecu, instrument cluster panel, and speed sensors. All of these are good. Its something between the vecu and the cluster panel. Am I missing something?? I need some wires to check? Thanks for the help?

 

Its mind boggling, but it almost has to be a simple error somewhere. We rebuilt the engine and installed it. put the transmission all back in the way we took it out. We had a problem before, with another truck, where we put a different transmission in. The problem we had with that on it was the wrong sensor for that truck and the signal was wrong. It was giving a vehicle ecu fault. This one is a different fault. What i'm getting is a Mid 128 pid 84 fmi 2 fault in the engine diagnostics and a Mid 140 pid 84 fmi 9 fault in the instrument cluster diagnostics. What I can gather is "Incorrect data, Communication fault, abnormal update rate". Its like the cluster can't read the data its been given. If it was lack of power than it would read "electrical fault".