Axle clicking is always due to CV wear, brand new CVs will not click in 4lo on any surface. The click is caused by wear between the inner & outer race that allows the bearing enough space to slip between the races in the sound of a "click." In TOD mode, the transfer case has little or no power to the front wheels when making tight turns (at low speed) and not enough to cause bearing to slip. 4lo is a great way to check a suspect CV issue and I agree to never use 4lo on dry payment.