The truck will go into reverse, but will not go into drive or any of the other gears. When shifted into one of those gears, it just idles as though in neutral. This started as I was driving down the highway at approximate 70mph. The speedometer jumped up then fell to zero as the car slowed to a stop. There was no noise except the sound of rapid fuel intake and then it went to idling. Any help would be greatly appreciated. I have been told it may be a speed sensor, but I was wondering if there was anyway to confirm that before I have the truck towed down to a mechanic and find out its more than I want to pay to fix it.
If the truck won’t move at all when put in drive then you have a bigger problem than just a speed sensor. A dead speed speed sensor might leave you with something like second gear only (limp mode) but it won’t kill all forward engagement.
Have you tried to put the shifter in its lowest position (“L” or “1”) to get going? You might be able to drive the truck in starting with L/1 and manually shifting it up. If it goes fine that way I’d say there’s some hope that your problem is less serious than needing a complete overhaul.
Its likely that your check engine light came on during this episode. This means that there are error codes stored in the computer. You can read those yourself - here is an explanation of how to do it: http://dodgeforum.com/forum/general-tech/8717-service-engine-codes-for-obd-engines.html If you get some codes go ahead and report the code numbers here.
Either way it will likely need to go to a good transmission shop - one that does specialize in transmissions, and is local and independent - i.e. not a corporate chain operation.