I have a 2001 Grand Caravan AWD. It has just under 75,000 miles on it.

Last weekend, the wife was driving it on a long trip with the youth in our church when all of the sudden it started making horrible clanking noises and it would lurch forward. We had it towed home so I could take a further look at it.

It is still drivable at VERY low speeds (1-2 mph), but about every 10 or 15 feet it makes a horrible clank like something is binding up and then brakes free. I watched, and when it makes the loud CLANK the entire engine is jerked back a couple inches. (note - this happens driving straight in both drive and reverse) When going slow enough, only a slight clank is heard. But anything near 1-2 mph and the clank is REALLY loud!

I took out both the front axles and the CV joins seem to work fine and there isn't anything I can see that would cause the binding. (boots are still in perfect shape) But the noise is definitely coming from up front.

I'm guessing it is either the tranny or the PTU (power transfer unit) for the all wheel drive. Anyone have any idea?