2003 Chevrolet C4500 Kodiak C4C042 8 Cyl 6.6L
speedometer reads 85 mph actual speed is 35 mph, govenor kicks in. What could it be?
Nissan Technical Advisor 7/10/2011
Probably a bad vehicle speed sensor. Have your vehicle checked for diagnostic trouble codes to verify the given fault. Post it here so we can help you in translating the code/s and provide repair recommendations.