P0503 problem
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P0503 problem
I am new to the forum and I am looking for some advice. I posed the situation to one member and he gave me some valuable advice but I wanted to see what others thought. I have a 1998 F150 that had code P0503. I took it to the dealer and had the speedometer drive gear replaced as well as the sensor. Picked up the truck and everything worked great. After driving approx. 600 miles the vehicle started shifting hard just like it did before the repairs. Returned it to the dealer and they said they THINK it is play in the output shaft in the transfer case. I would have thought if there was play in the output shaft the problem would have resurfaced before 600 miles. Is it possible the sensor that was replaced has failed already? What is the best way to test the wires to the sensor? At this point I am not sure what to do next and I am having trouble believing the dealers diagnosis. Any suggestions would be greatly appreciated. Thanks in advance.
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From: New Holland
I believe most sensors of this type have 2 wires coming from them. The sensor puts out an ac voltage signal, which increases voltage with increased speed. Try disconnecting the sensor connector and using your voltmeter check for ac voltage, if no voltage is found remove the sensor and look inside the sensor mounting hole for a toothed or grooved wheel which turns the sensor creating voltage. If the sensor drive gear is damaged or missing it will cause the sensor to not spin meaning it will not give off a signal. You will need to have the drive gear replaced again, most likely there is something wrong internally if the drive gear has failed again. I would take it back after checking it yourself and make them pay for the repairs.
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I removed the sensor and felt inside the sensor mounting hole and the drive gear spins freely with my finger. Is it possible that it was a faulty gear? After the repair the vehicle worked flawlessly for 600 miles then it threw the p0503 code. I would have thought if the output shaft was bad it would have threw a code before 600 miles or if there was that much play that it would have knocked out the rear seal in the transfer case. Thanks for the reply.
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I returned the vehicle to the dealer to have the drive gear inspected and or replaced. The dealer installed a new TSB gear and informed me that this gear also has some play on the output shaft. At this point they are only guessing as to why the new gear would have some play. Anyone want to take a stab at this one? Thanks for the help.
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