Put about an ounce of friction modifier in the front diff. Hopefully my chattering goes away. I think the dealership I bought it from serviced all the fluids and didn't put in enough, or any at all. The rear seems ok so far.
98 5.9 Limited - IRO 3.5", IRO short arms track bars Bilsteins, Addco, JK wheels, 255-75/17 BFG, Magnaflow, Flowmaster
04 Limited 4.7H.O QD, UC+BB, Bilsteins, 245/75-16 Duratracs Addco sway bar