UPDATE: RESOLVED. It ended up being that the Speed Sensor part that was bought was defective. Once it was replaced again, the transmission functioned normal but took some time after resetting codes for the blinking 'off' light on the overdrive to stop & return to normal.
in time the This is a bad situation in that the transmission scanner gives a reading the truck is in 2nd gear when it is in park running, so it is gaining a signal from something, not losing a signal. The overdrive "Off" light began blinking intermittently, even if you were just sitting in park. The transmission code reader came up with P0720 Speed Sensor Circuit Fault so the speed sensor was changed. The overdrive light kept blinking. It is a false electric signal coming when the motor is running, still giving a reading as though the truck is in 2nd gear, although it is in park. So, it was determined the alternator diode was bad, so the alternator was changed believing it was causing the signal. Now it has been $245 in replacement parts & wasn't the alternator, it's definitely in the wiring, but no one now has an idea which one after earnestly trying to work very hard to find what the problem was. I'm worried. I have to travel a very long distance from Central Wyoming this coming weekend to southern New Mexico & this has become a safety issue taking up the small amount of travel money I had with a very short time now until departure time. I would like anyone that has had experience and successful resolution of a miserable problem like this to please try to help & tell what you have done to overcome this type of a ghost mess where the best of them are trying so hard & can't crack what's going on here. I so much appreciate any experiences where someone understands this issue well.
in time the This is a bad situation in that the transmission scanner gives a reading the truck is in 2nd gear when it is in park running, so it is gaining a signal from something, not losing a signal. The overdrive "Off" light began blinking intermittently, even if you were just sitting in park. The transmission code reader came up with P0720 Speed Sensor Circuit Fault so the speed sensor was changed. The overdrive light kept blinking. It is a false electric signal coming when the motor is running, still giving a reading as though the truck is in 2nd gear, although it is in park. So, it was determined the alternator diode was bad, so the alternator was changed believing it was causing the signal. Now it has been $245 in replacement parts & wasn't the alternator, it's definitely in the wiring, but no one now has an idea which one after earnestly trying to work very hard to find what the problem was. I'm worried. I have to travel a very long distance from Central Wyoming this coming weekend to southern New Mexico & this has become a safety issue taking up the small amount of travel money I had with a very short time now until departure time. I would like anyone that has had experience and successful resolution of a miserable problem like this to please try to help & tell what you have done to overcome this type of a ghost mess where the best of them are trying so hard & can't crack what's going on here. I so much appreciate any experiences where someone understands this issue well.
