I found it!!! I took apart my door and that wasn't the problem. I took out my passenger seat and pulled up the rug and it turned out to be a faulty relay, connected to the stereo preamp (40A/30A 12VDC). It sounded like a rattle in the door. The funny thing is that when I would hit the gas or brakes it would make a mechanical buzzing sound which is why I couldn't figure out if it was electronic or just something loose. When I held the transformer it REALLY made a buzzing sound. I unplugged it and the noise stopped (it was SOOO irritating and loud!). When I unplugged it the 'CHECK' light under the torque on demand 4 wheel drive light came on. The car seemed to run OK without the relay/transformer but I'm not sure how important it is. I thought it was just for the preamp which was installed under the passenger seat but it appears to affect the Torque On Demand in some way. Thanks for everyone's help! I'm uploading a photo of the relay to this thread in case someone else needs to know ...
P.S. Turns ut I can't upload photos here so here is a link to the relay:
http://www.in-car-stuff.com/shop/relay-spco-p-59.html

My relay says it's 40A/30A 12VDC