It engages at the tranny but not the hubs. I had the front of the truck in the air, turned on but not running, and hit the switch on and off, the hubs locked and unlocked. I was turning the wheels by hand to tell. When I pulled it out of the garage they wouldn't lock. and again i was stuck trying to climb my driveway in the f*ckin snow in reverse.

Same results in low or hi.

I pulled apart one hub to see if they were full of crap and they look mint inside.
This truck doesn't see much muck.

I sifted through the threads already, but links are welcome.

Thanks to all who help

 

ive heard that the vacuum lines that engage the hubs are often the issue if not that then the actual solenoid also. havent run into this yet but thats what i have heard, someone in another forum im on said that he had this issue and one of his vacuum lines were cracked so he replaced itt and it was fixed

 

A little information like the year, model, powertrain configuration and etc. about the truck would help..

 

ok... 2004 F150..fx4, 5.4L, 4x4, crew cab.
electronic **** style 4x4

From what I gather the vacuum keeps the hubs DISengaged....correct?
My problem they won't ENgage, so leaky vacuum lines would give me problems of always being engaged...make sense?

please correct me if i'm wrong.

Information on how to test the vacuum solenoid might help........i'm grasping if i'm in the right area but...

thanks guys

 

Here I found this maybe it will help

leave the engine running with the truck in 2wd..... then go out and try to spin the front axles by hand.... they should move easily without any "binding" feeling.

what year is the truck? how many miles? it really sounds to me like you have a bad actuator. and, one bad one can cause the other to go bad if it has a vacuum leak. if it doesnt have a vacuum leak, but instead is just really sluggish and doesnt fully disengage, then you can ultimately eat up the wheel hub.

you see, the way these actuators works is this:
the have an internal spring which applies pressure to expand them. the inside of the actuator (towards engine) sits still, and the outer side (towards tire) will do all the movement. when you apply engine vacuum (2wd) you are over-riding the spring tension, and compressing the actuator. this pulls the toothed ring off of the wheel hub. the toothed ring is part of the actuator, and it rotates with the axle shaft...... it is always engaged to the axle splines. and, then when you switch to 4wd, the solenoid dumps the vacuum from the actuators, and the spring then expands them. this forces the toothed ring outwards, and engages the axle shaft to the wheel hub.(it is about just over 1/4" wide, and rides half way on the axle, and half way on the hub)..... yeah, not much really grabbing there..... not very strong, but seems to work ok.

 

The "hubs" in your truck are called Individual Wheel Ends (IWEs) and actually lock every time you shut the truck off. That's because they use vacuum from the engine to unlock. So, your IWEs should be locked (if they're working properly) when the truck is shut off. If you use the seach function, you'll find lots of helpful posts on the subject of IWEs. And yes, they do have a nasty habit of going bad just when you need them most.

The second problem you might have is the dreaded Electronic Shift on the Fly (ESOF) motor failure. If the motor isn't working, you're not shifting the transfer case into and out of 4 wheel drive. The first thing you want to do here is verify whether that bad boy is working or not. Believe it or not, sometimes a few love taps on the side of it (located on the back of your transfer case) will free it up. If not - and if it's shot - they're pretty simple to replace. Again, use the search function for lots of good (and some bad) advice.

 

The transfer case seems to be working. I feel and hear the click going in and out of 4hi and a little more clunk going into 4lo....that being said I know its in 4 lo cause its got mad *****, but no 4by...does this verify my transfer case motor is working?

thanks for the tips guys....

and for anyone reading this....keep the ideas coming if you know if any of this information is bad, misleading or missing some key information in some way....

 

thanks for workin for me dude...mucho appreciated.

 

Best way to verify it, is to jack up the front of the truck.

Turn the key from off to run ( do not start ), turn the ESOF switch to 4H or 4L try to turn the front drive shaft.

If it does not turn, the transfer case shift motor should be fine. You need to verify if the front drive shaft is still free while in 4WD or not. Anything else is really a SWAG, not an answer. I know I have done this myself, and it always bites me in the rear end when I skip a step.

The other test is to pull the vac lines on the IWEs, and plug the ends of the vac lines ( so you do not have a vac leak ).
If it works this way, could be the IWE solenoid is not shutting off the vacuum to the IWEs ( goes against the KOEO test you ran ).
Don't know if the vacuum reservoir has vacuum in it to make the KOEO test you did with the hubs locking in and out while the engine is off work, never tried myself.
Don't know if the IWEs engage each time you turn the key off, or over time from sitting, have never checked it myself.

 

OK, so the transfer case is working. That's good. That means it's either the solenoid the controls the IWEs, the vacuum lines that run from the solenoid to the IWEs, or the IWE's themselves. Use the search function to look up a post from TNF150. He posted up a really good thread that also included a pdf file on troubleshooting the system. The good news is that if you're handy at all, any of the problems I mentioned can be fixed by you. I used TNF150's posted intructions to replace my IWEs and it took less than an hour total. The solenoid is even faster - and cheaper too!