I have an 05 f-150 with the manual transfer case. when i put it in 4x4 high or 4x4 low the front driveshaft spins but the hubs never lock and my rear tires just spin. my front tires dont pull at all.

what could be the problem?

 

Vacuum actuators that engauge the "auto" hubs. If you went wheeling or something you may have managed to disconnect the vacuum lines.

 

ok thanks i will check that out because evryhting else is working fine and i hardlly evr use it but teh other day i got the urge and went playin the mud. where do i check the hoses?

 

The default position for the front is locked without vacuum. Put it in 4x4 and park then lift the front wheels off the ground. If the drive shaft turns the problem is in the t-case. Most likely one of the front IWE hubs is stuck in the unlock position.

 

As far as i know the default is unlocked, Im a Ford Fact graduate and have never heard of the hubs being locked all the time.

 

Without vacuum the default is locked. This allows the use of 4x4 if there is ever a vacuum leak in the IWE system.

JMC

 

Well i have seen trucks with broken vacuum lines that the hubs would not engage. It would make sense that they are applied vacuum all the time, and it is released when put in 4x4, but i'm not a ford engineer, i only know what i have seen and worked on.

 

The IWE uses a spring that pushes the collar to lock the hub. When vacuum is applied the spring is pulled back, the system releases and the hub is unlocked
If the seals leak and water is present the system will not work properly and engagement can be compromised. The IWE system was Ford's way to recoup some MPGs by unlocking the hubs and removing the drag of turning the front carrier pinion gears like the 97-03 system.

JMC

 

Well you learn something everyday, thanks for the info. I haven't had to work on any of the NBS 4x4 systems.