How do I know if it's my input or output transmission speed sensor ?

Question

I have a 2004 chrysler sebring 4 door my speedometer jumps up and down sometimes then my car will throw itself into 1st gear and won't come out until I cut the car off and on and then it's fine until it does it again someone help

Jackolantern · Answer

The gear that was used in the past for the speedometer was on the output side of the transmission. Same with the sensor on today's vehicles that operates the speedometer. The output sensor. The input sensor is for the RPM going INTO the transmission.

One Horse Pony · Answer

It would most likely set a DTC. You would need a scanner that can read transmission DTCs. The only DTC that would be present in the PCM would probably be a P0700 which tells you nothing except that there is a fault with the transmission. If your speedometer is acting weird then an output speed sensor would be a good bet.

thebax2006 · Answer

Most input and output speed sensors on the transmission won't effect the speedometer. 
You need a mechanics $3000 scan tool to read tranny codes and read the transmission sensor and solenoid data to diagnose which sensors or solenoids are not working.
A bad input or output speed sensor will cause the vehicle to go into limp mode/fail safe mode and the transmission will only have 3rd and reverse gears.

Anonymous · Answer

Get a scanner that can check transmission trouble codes.

don_sv_az · Answer

If the speedometer jumps up and down it is likely the output sensor. The input sensor has nothing to do with the vehicles speed.

How do I know if it's my input or output transmission speed sensor ?

5 Answers