I have a 2001 Dakota. I just noticed a loud knocking noise somewhere in the front end when the 4wd is engaged and driving forward. The noise sounds like metal on metal. Any idea what's wrong?

 

Does it only do it when in 4? If it is, then I would look at possibly your t-case. I ended up getting mine warrantied after it started making a knocking, ratcheting noise. I had only had the case a year and the company said that it sounded like the shifting fork not keeping it in gear.

 

its probably the cv joint on the tcase/driveshaft side. get under there and see if the rubber boot is torn.