Jack the front of the truck up so both wheels are off the ground, manually lock both hubs in, then spin the wheels by hand while watching the front drive shaft, and see if it spins. If it doesn't you either have an issue with your hubs not engaging properly, or you have a serious issue in your axle. You can test the vacuum hubs this way also, put both hubs in auto, start the truck, turn the switch to 4x4, and turn the wheels again by hand while watching the drive shaft again, and see if it spins, if it does, then they are engaging, if it doesn't then there again you either have an issue with the hubs, or the axle.

 

Ok will try that this evening. Thanks for your help.

 

Trying to test if both hubs are working, you DO NOT jack the front up off of the ground to do the test I said previously.

 

Only adds confusion by doing it that way, if everything is working with the hubs locked and in 4wd with the front off of the ground the front driveshaft will not turn when you turn one of the front wheels by hand, and the other wheel will turn the opposite direction since it is an open differential.

 

CargoMaster I will lock front hubs in and see if front driveshaft turns in 2wd. Will report back this evening after work.

 

So 2 quick tests I'd do.

xcase in 2wd mode, lock the front hubs, drive forward and back a little to try and ensure the hubs engage. Now climb under and try and twist the front driveshaft. The xcase is in 2wd and the front driveshaft should be free to move, BUT you've locked the hubs so it should not move. If it does your issue is in the front axle, either a hub is not engaging or is internally broken, or amazingly you've broken silently the differential (if recently you heard a bomb go off in the front end and the diff cover has a quarter sixed hole in it we're wasting time here). So look to the front end.

Ok that worked, the front driveshaft wouldn't move because the hubs were locked. Now disengage the hubs and drive forward and back a few times to try and make sure the hubs are disengaged (if you still have the disasterous vacuum hubs system disconnect the lines right at the hub so it can't engage the hubs) , still in 2wd, try the driveshaft again. It should now turn as the hubs and the xcase are disengaged. That works? you can turn the front driveshaft? Now put the xcase in 4wd, leave the hubs disconnected, put in park, try the driveshaft, it should be locked meaning the xcase is in 4wd and now going to try and drive the front axle, if it still turns by hand while in 4wd with front hubs disengaged you have an issue inside the xcase. Maybe next you can put it in gear and drive forward slow while someone watches, the front shaft with the hubs disconnected should turn on its own (it just won't drive the disengaged front hubs).

This should at least get you to where to concentrate your efforts.

 

You don't have to drive any to engage/disengage the hubs turning the driveshaft by hand will do that.

 

Yeah, you're right. It was late when I wrote that, and I don't know what I was thinking. Another way you could check it is if you jack up one wheel off the ground, lock the hub in manually and try to turn the wheel, if the hubs are working, you won't be able to turn the wheel, if the wheel turns, then the hub isn't engaging or you may have an issue with your axle, and if the drive shaft turns while doing this, it might be an issue with your transfer case. Switch the hub back to auto, start the truck and switch it to 4x4 and try to turn the wheel again, if you can't turn it the auto hubs are working, if you can turn it the auto hubs aren't working. Repeat in the other side. this'll tell you the condition of your hubs as far as whether or not they're locking in or not at both manual and auto. But like others have pointed out, there's multiple was you can test them, so just do whatever way is easiest for you.

 

Ok was able to do this today when I locked the front hubs and truck is in 2wd the front drive shaft still spins. Where do I go from here?

 

Look and see which axle behind the front wheels is spinning when you turn the driveshaft, the one that is spinning is the side that the hub isn't engaging on. Are you sure you turned them the right way? Clockwise to lock.

 

Yes sir I’m positive I turned them to lock. I will try and get that done tomorrow evening. Thanks for your help.

 

It’s the drivers axle that is not turning. When I turn drive shaft one way then the other I can see it wiggle but that’s all. Wouldn’t this mean something is broke in front differential?

 

If the passenger side is turning when you spin the driveshaft by hand with both hubs locked then the passenger side hub isn't locking.

 

Ah got it. What would be your next move on trying to figure out problem?

 

Yes, pull the hub off and see what is going on.