wondering about how the system works. right now i can see the knuckles at the front tires turning is that normal when hubs are not locked. the front drive shaft is free... i have auto locking hubs. i bought warn manuels that i have not installed yet. is there anything else i should be looking at that will cause the 4x4 not to engauge.
thanks in advance

 

What are you working on, a K5? S10 Blazers do not have locking hubs, and there are no manual hubs available. We need a little more information before we can help you.

 

Sorry. It’s 84 k5 blazer

 

Automatic hubs are supposed to engage when you shift to 4WD and disengage when you back up in 2WD. I've always replaced them with manual hubs on any truck I've owned, since they aren't very reliable. when you say the front drive shaft is free, do you mean you can rotate it by hand? When you do, do the front axle shafts turn? If you jack up a front wheel and turn it, does the shaft rotate? It's a pretty simple system. You just need to figure out where the "disconnect" is by trying to turn the components independently. For example, if the axle shafts can be turned while the wheel is stationary, the hubs aren't locked. If the driveshaft can be rotated without the acxle shafts rotating, the problem is in the differential. If the hubs are locked and you can't rotate the driveshaft by hand, but 4WD still doesn't work, you have a problem in the transfer case.

I would start by replacing the auto hubs with the Warns. It's an easy job, and it will eliminate one common failure point. That should make your troubleshooting easier.