Rds were icy had it in 4 high on Highway. Bad oily burning plastic smell so bad I had to roll all windows down and I could even taste it. Took it out of 4 high into 2 high. Speedometer stopped working abs and brake lights came on and smell went away. I knew from past experience that those 2 lights and speedometer not working meant the speed sensor went. Now the 4 wheel drive isn't working. I put it in 4 wheel drive and the front driveshaft spins , the back tires spin in the snow but the front tires don't move at all. Could the front differential be gone now? There's no noise coming from front differential. Would being low on fluid in the differential be the problem? I really need to fix this so I can get to work when the weather is bad because dakota's suck in snow in 2 wheel drive

 

Sounds like you toasted the front diff. If the drive shaft is turning but the axel isn't it sounds possible. OTOH if the lock isn't engaging the front wheels won't turn unless the vehicle is moving. Your description of the smell sounds almost like electrical which "could" be the problem. The selector is electrically operated and if the wiring went bad it may have been burning up giving you that smell/taste. Sounds like the need for a lift and a garage to do some serious troubleshooting. I'd think that low diff fluid would more likely cause noises as in dry gearing and bearings.

 

A 2000 is mechanically actuated, no electrics.

Pull the cover on the front diff. Start from there.