Hi All. Happy New Year
Sorry if this is long. I want to be as detailed as I can be.
I have read a bunch of threads and watched a bunch of videos. Checked and fixed many things, so here I am
2005 F150 5.4
The 4wd does not engage.
Replaced the vacuum solenoid as that went out on mt F150 and my sons a few years ago. Figured would get it for my dads and hopefully that would fix it. Cheap insurance just in case, so now my dad has an extra one incase it does go out.
So I dove in a little deeper. Did a vacuum test on the wheel actuators. Both sides held vacuum great. Then found that I was not getting vacuum in 2wd at the wheel actuators at all when running. Followed the lines and found a hole in the vacuum line. Fixed that. Still no 4wd.
Tested the transfer case motor. Works just fine. Checked the transfer fluid level. Looks great. Still no go.
So I had my girlfriend drive it on an incline in the snow and spin the wheels. Then I heard it. Hard to hear inside the cab. There is a rattle/grind inside the passenger side hub area. There is a video attached that I took of it.
Before I take the time to tear it all down, can anyone recognize what that is? Sounds like it is just spinning inside.
When testing, the cv is spinning on the passenger side, but not the drivers side. I am assuming that is because if 1 is shot, it won't be spinning the drivers side. Just all the power is going to the broken side.

Am I way off on this?
Thank you all so much for any and all help.

 

what did you do the vacuum test with ? sounds like a bad IWE.

 

No vacuum in 4x4 is correct, vacuum in 2WD is correct. You might want to check the 2 one way check valves in the vacuum circuit. Make sure that the IWE solenoid on the fire wall and see if it produces at least 20 inches of vacuum and if it checks out OK hook your vacuum pump to the vacuum line you pulled off the IWE solenoid and see if you can pull 20 inches of vacuum and see if it holds vacuum for a minute and report back
but it sounds like the spring in the IWE hub is week and not letting the hub to fully engage if vacuum checks out

 

Get these and be done with the vacuum system problems.

https://www.dormanproducts.com/p-101732-600-405.aspx

 

I will do some vacuum tests and report back.
I guess I am a bit confused. If there was no vacuum at the hubs, wouldn't I be in 4wd at all times and unable to put in 2wd?

 

2wd yes no vacuum at the hubs= full hub engagement 4x4, switch to 4x4 it pulls vacuum releases the front hubs but you could have a slow leak in the vacuum circuit and that side bleeds off a little causing it to partially engage. Biggest thing to do first is to make sure you can pull vacuum at all hoses and they hold. You can pull the vacuum lines off the IWE hubs and put it in 4x4 and if it engages you have a vacuum issue

 

Test results.
2wd
Vacuum before the solenoid valve on firewall is a steady 16 (maybe a hair more)
Vacuum after the solenoid valve is a steady 16
Vacuum at the hub actuators is a steady 16
When I hooked vac gauge to the actuators and pumped it up, they both held steady at 20 and didn't drop, so I believe that means they are still good.

Is the video working? It almost sounds like everything is working, but the gears or teeth are not meshing

 

It kinda sounds like what you said about the actuator spring. It may hold vacuum, but spring is not strong enough to engage the 4wd?

 

Something new just tested.
This is with truck turned off, so obviously no vacuum.
Pulled the cap off the wheel. Pulled the dust cap off. The nut on the cv end should not spin.
It turns and I can hear the sort of grinding noise that you can hear in the videos.
I would have to say that it is the actuator not engaging the hub correct?
The drivers side does not turn.

 

I would say spring is bad but replace both IWE hubs that but be prepared to replace the wheel hub bearing on that side or just do both sides also for piece of mind. Rockauto.com is your best bet

 

I can give you part numbers because I just did all this to mine last week lol

 

Thank you all very much.
Not looking forward to the job at all, but it is what it is.

Looks like each actuator is approx $80-$90 or I can get the kit of 2 actuators and vacuum solenoid for $128. I think I will go that route. DORMAN 600305 correct?

How was the job for you?

 

Its not bad at all, there are plenty of videos on YouTube that explains everything yes correct parts

 

Do not buy Dorman. There are reputable, real live Ford dealers selling IWEs on ebay (or just call them directly). Now someone is going to scream everything on ebay is counterfeit but this is not true if you know your seller.

Do not buy Dorman.

 

Here's a real one from a Ford dealer:
https://www.ebay.com/itm/135804953665

Despite the Motorcraft boxes this is 100% counterfeit, and if you filter negative reviews you'll see he also sells fake video games and printer cartridges