I tcheking my front driveshaft joints and there is a little loose at the universal joint(differential end) and more loose at the transfer case end.(moving a lot when I take the cone of the cv joint in my hand and shake it).

my question is when the truck is on 2wd,the front drive shaft surelydon't spin...I don't know how it can make my noise?even if the joints are run out.
When I push on 4x4 hi,I feel very weel normaly engage and the noise stop.

(I spinning the wheel on the snow on 2wd and the front wheel not spin,then I assume that is disengage well)

Thank you guys to take the time!

 

The front axle disengages at two points. The transfer case stops sending power to the front drive shaft, but also, the differential disengages from the axle as well. This is why the front drive shaft should stop rotating. If the front axle is not disengaging at the differential, then it may amplify the faulty joints in the front driveshaft.