The speedometer on my truck stays at zero and won't shift gears unless I do it manually. Even when I shift it manually it won't shift into third unless the speedometer is working. And the speedometer only works when I'm going highway miles then I can shift it into third and then into overdrive. However sometimes when I can shift it up into overdrive the speedometer will drop down then go back up and when it going down my rpms rev up. What could it be?
My car has 180000 miles.
My car has an automatic transmission.
Hello, thank you for writing in. Since the speedometer reads 0 instead of bottoming out, I would say the problem has to do with the signal coming to the speedometer. This could be from something such as a sensor failing intermittently. This may be related to the same thing causing the improper speed reading. If the vehicle does not recognize the speed signal, the transmission performance may suffer. Consider hiring a technician, such as one from YourMechanic, to look further into your vehicle and offer a personal diagnosis.
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