4WD Front Hub Not Engaging
 

My answer is likely on another thread but I couldn't find it.

I have an 09 FX4 with a front hub that's having trouble engaging. I can hear/feel it trying to, but no cigar. What is my likely issue(s)?

probably poor vacuum pressure. do you have a gauge to check it?

Vacuum hold's the wheel end out "disengaged" If you are having issues with engagement it would be a venting issue or stuck wheel end.

My guess is it's gunked up. But the solenoid might not be venting as it should. You'd think it would be both IWEs if that were the case. If you've had the grinding in the past, it might not have any teeth left. What makes you ask?

Thanks for the replies guys. I don't have a warm dry place to check it out so you've given me some things to check when I do. I was just wondering if this was a common F150 hub problem.

I'd prefer the good-ole Warn Hubs that I usta run with - I always knew when they were in! Is the vacuum coming from engine vacuum right? So the gear that moves and engages is located in the hub and held with vacuum? I've never hadda work on any of my Ford's front hubs so this is all new to me.

I had her stuck in the mud pretty good this summer and first noticed that I had trouble getting the front to spin. It seems to "buck" when I accelerate trying to engage now. Yeah, at this point, I probably did some damage to the teeth. It's a good truck that I'm going to try to hang onto for my heavy lifting, and I'll continue to use my Focus ST for the daily driver stuff.

I just dealt with this on our '15 F150, my 'auto-locking actuator' was broken on the drivers side. We didn't have 4WD since it wouldn't engage, which isn't great going during Winter!! On our truck, you could actually hear the front end grinding as the teeth were trying to mesh. It's actually a fairly common issue, could be lack of vacuum as mentioned or the hubs themselves. IMO it's a flawed design. What's funny, since you mention Warn hubs.... and I am a Warn fan, but these factory auto-locking actuators are actually made by Warn! Both the old one I pulled out and the new one I put in had 'WARN' stamped on them!

The work took about 2 hrs on the one side, wasn't too hard to do either. The parts cost me $70/ea. When I pulled the old hub out, it came apart in pieces.

LOL - yeah, I should'a said "Manual" Warns. I'd love to see an exploded view of what's in there - I did a quick search but didn't see anything. I'm guess'n I'll find something on YouTube. ;)

Do a google for Makaloco, I think that's how you spell it. He's got some good videos out there, and one specifically address's replacing a Ford IWE.
Something you could try without much trouble.
Firstly, yes, vacuum is supplied by the engine, and on some there is also an electric vacuum pump, I think on the 11th and 12th gen trucks, and possibly pre Eco II engines, '15 & '16. Don't hold me to that, mines a '17, and a Gen II Eco, it has an entirely different vac system.
Anyway, jack the front end up, both sides, with the engine OFF, see what happens if you spin the front wheels by hand, they should be engaged to half shafts, and you should see the halfshaft turn.. Then start the engine to get some vacuum and do it again, the halfshafts should be disconnected, and not spin.
I'm seeing a misconception here in this thread. Vacuum holds the IWE DISENGAGED, lack of vacuum, the IWE's ENGAGE.
After you try this test, let us know what you find, it could be the Tcase not engaging 4X4.
10/4 on manual hubs and manual Tcase, a lot more foolproof, but requires a little physical effort that not many are willing to exert, might take away their texting strength for the cellphone.

Fordtechmakuloco