Okay so I'm driving around and I notice that my speed doesn't register until I get to about 35mph. I also that the odometer doesn't advance until I get to the same speed. I'm guessing they are related but how do I fix it?

 

about the only thing i can think of is a tranny sensor. its a stretch but i had a dodge neon that did that. the tranny sensor on it was placed poorly so when i went through puddles, water would get into the sensor. my speedo would bounce, and then stopped working after awhile, same with the mileage, it stopped racking up mileage. i dont know if durango is built the same as far as that goes, but thats my guess

 

It's not the sensor on the tranny it the rear speed sensor , it can be found on the top of the third member near the drive shaft. The part runs about $45 at your local dodge dealer.