I have an 05 6 liter that has the auto locking hubs and they are locking in for no reason at all...switch is still in 2wd and the hubs are in the auto free position but when you start driving it engages itself into 4wheel drive...it has brand new hubs new seals everything does anyone have any idea why it's doing this?

 

The hubs locking (or being locked) will not cause 4wd to engage; they have nothing to do with the transfer case.

Is your 4wd light turning on by itself while you're driving?

if the hubs are simply locking, you can either pull them apart and clean them, or just stick new manual hubs in (that's what I did in my 2006 5.4l)

 

You did not say if your truck is gas or diesel. If its diesel you can try this with key in run position, and if gas, engine needs to be running.

There are 2 vacuum lines going to your hub lock solenoid. Find the line that does not go back to the reservoir. Follow this line to the 90 degree junction where you can pull the line apart. If there is vacuum suction on the line, then your hub lock solenoid is stuck in the 4x4 position. There should only be vacuum on that line for 2 minutes after engaging 4x4, so if vacuum is always present, it will keep engaging the hubs.

Other possibility is that your hubs never unlocked. Mine did that because the aftermarket solenoid I had on there did not produce enough vacuum to unlock them when I selected 2x4.

 

 

I'm not sure how the new ones are but for mine if you kneel in front of your wheel: rotate the selector counter-clockwise for auto and clockwise for lock.

 

Years ago, I had a 4x4 dash switch go bad. Easy fix if that is it..
I thought it was the relay (replaced it), but it was the switch.