Is my 97 Dodge Caravan speed sensor going bad ?

Could be the speed sensor or the speedometer. The speed sensor signal is processed at the speedo then sent to the computer, which controls the transmission shifting. Don't drive your van this way or you'll burn up the tranny driving around in first gear. I think it's more likely the speed sensor. The speed sensor is mounted on the transmission. If you're not sure about where it is, check the service manual. To test it, pull it out and bridge the contacts with a voltmeter set to ac volts. Give the little gear at the end a spin. If you get ac volts, it should be ok. If not, you found your problem. If you're not too familiar with these sorts of things, just take it in to the shop. The labor shouldn't be more than 1/2 to 1 hour at their standard rate. Not sure on parts cost. If it's the speedo, then it's going to be more painful. At least 2 hours labor and pricey on the part. Plus you'll have to notify the county and/or state since it'll reset your odometer. Good luck and happy holidays.

You may have a problem with an input or output speed sensor on the transmission. Any ses light on? If you can't go fast and the motor is at a high rpm you probably are in the fail safe mode and the transmission won't shift. Go get it scanned by a Dodge Technician so you don't start throwing parts at it.

if it's a 4 speed, these sensors are notorious for going bad. there is an input speed sensor and an output. might as well replace both. go to your dealer for them. part numbers 4800878 and 4800879. if you're halfway mechanical, they shouldn't be too hard to replace. they just screw into the outside of the transmission case, but you got to get to them first. the parts should only cost $15 apiece, anymore and it's just extra markup.

I'd be checking for any codes that might be stored related to that problem bec it sounds like the transmission comp=TCM went into the limp mode or safe mode.The transmission comp will cause the speedo and RPM gauge to stop working and the transmissions 2 emg gears will only work and you could burn the transmission out if you drive over 60 kms per hr or you go over 3,500 rpms steadily. It's not really hard to change the speed sensors but there are 2 of them and you need to know if it's even a sensor problem and what one it is the input or output speed sensor.They sit right on the transmission and can be seen if the van is up on a hoist or stands etc. Hope that helps and best of luck.By the way if you try turning the ignition from the Aux positionto the run position3 times then leave it in the run positionyou should notice the engine light flashes.If it flashes once then pauses then flashes twice that means code 12=battery has been disconnected at some point in time , if it flashes 5 times then pauses then 5 times again thats code 55= end of cycle no more codes stored.I'd be checking for these codes and others then finding out what they mean bec many different things can cause that problem. By the way was it really cold last night when this happened?One cause of this type of problem is faulty connections etc or corroded wires or internally corroded wiring in the transmission electronic circuit.