Instrument panel problems (stumped speedometer shop).

Symptom: Everything EXCEPT Odometer and Tripmeter works. (note: speedometer DOES work so that would usually indicate NOT a signal problem but likely gear problems)

Description: 1992 Camaro Z28 (V8 5.7L TPI)
NOTE: This is a factory CANADIAN 245KM (140mph) V8 350 instrument panel. About 2 1/2 years ago my tripmeter stopped working. Not really necessary so I left it. Shortly later my repair shop noticed my odometer has not moved since 2010. I too looked at all my receipts and discovered it in fact has remained exactly the same since 2010.

I was told to take it to a speedometer shop who deals with speedometer repair. They took the speedometer out and 2 hours later called me to report they are stumped.

Problem: They explained everything seems fine. They hooked power to the speedometer motor and it works perfectly fine. Tripmeter is also perfectly fine. They explained that IF it were a problem with the sensor at the transmission that the SPEEDOMETER would too also stop working as they are all 3 connected to the same signal.

One part he is UNSURE about is whether or not the 1992 Camaro 245km (140mph) instrument panel (cluster unit in particular) use the SAME signal or in the speedometer signal SEPARATE from the ODOMETER and TRIPMETER?

IF it IS separate they he suspects the signal from the transmission is faulty. But if it's the same, then he suspects something to do with the circuit board they the speedometer assembly cluster where the odometer/tripmeter are all part of, is malfunctioning.

Since it's not mechanical, they are stumped as to WHY the tripmeter would stop working first and then the odometer 2 years ago if they are in fact all 1 signal?

Can ANYONE shed light:

1. Is the speedo/trip/odo meter are get their signal from the SAME sensor on the transmission? or are they SEPARATE?

2. IF I were to purchase a US 1992 140MPH instrument panel, is the ONLY difference just the speedometer cluster? What about the circuit board that the speedo/trip/odometer are attached to, are they the same? Basically would I be able to just swap out circuit board in the US version and connect to my CANADIAN version without any issues?

Thanks very much!