I'm not sure if this will help, but i have the same problem with my 2001 Dodge Dakota speed sensor ans speed solenoid it cost me $450.00 parts and labor. all I know is its inside the transmission and I dont really wanna mess with it myself. The speed sensor probably cost no more than $50.00. Good luck!
Hi,
The Vehicle speed sensor on your '01 Dakota is located on top of the differential, and is fairly easy to replace. Assuming the truck is on a lift, I'd say it's no more than a five minute job. You can get one at an auto parts store for under $25.00.
My 2000 Dakota 3.9L SLT had a ABS/speed sensor problem was inexpensive and easy to fix. My initial symptoms for the replacement were both ABS and brake light were on and speedo didn't work from 0-15mph. Everything is back to normal now. To replace the sensor you really don't even need a lift, a floor jack and 2 jack stands work just fine(If your pretty slim you should be able to fit under on a creeper and have just enough room.). I purchased the sensor at NAPA for $37 including tax. It took me about 20 mins or so. The time consuming part was getting the old one out and the new one back in without damaging it. Easy way to get the old one out is to take a flathead screwdriver and turn the sensor so the hole for the bolt is slightly over the edge of the steel and lightly pry through the hole until you have some space between the differential and the sensor. Next slide the screwdriver into the gap and work it all the way around the sensor until it slides out. The way I put the new one in work pretty well. Take a small rubber mallet and tap the sensor into the hole. Make sure you tap on the sensor not the female connection. It make some time but it worked for me and nothing ended up damaged.