4WD Front Wheels Not Engaging - I HAVE posilock
 

Sorry if this has been covered somewhere, couldn't get past all the noise about CAD issues in my searches.

Front wheels on my truck are not locking in 4WD. 99 1500 5.9 auto. I have a posilock so not the CAD I don't think. T case locks in fine both 4 hi and 4 lo. With posilock engaged, I can turn the yoke on front diff easily by hand and move the pinion gears (transfer case is out of truck for the moment for seals and diff case cover is off). The wheels do not turn. Shouldn't the front diff "lock" somehow? Like when tires are on the ground, turning the front yoke would be hard and move the truck? What am I missing here? is there something downstream in the axle or on the hub that needs to lock?

On the passenger side axle tube there are two axles, and there is a collar they connects them together. Check to see if that is happening. Your posilok only replaces the CAD with a cable. Now you can get a kit to eliminate the two piece shaft with a one piece

Sounds like your Posi lock isn't engaging, pull the cover off of the CAD and see what's going on in there.

Three possibilities come to mind; collar is stripped, cable has broken off from the fork, or the fork itself is broken.

CAD stands for central axle disconnect, Posi-Lok just changes the operation from vacuum to mechanical.