alright well i got a little more in depth with this thing today and i have a few more questions. first off i pulled the lines off the hub. put vaccuum to the hubs and it holds. so the seal is good. plugged the lines from the hub and put vaccuum on the it at the solenoid. didn't hold so i know i have a leak somewhere between the hub and the solenoid. now my next question, although i have vaccuum at the hub does it eliminate the possibility that it could be the actuator itself, or is it still possible that the actuator is bad but the seal is not? remember the grindin noise occurred long before the 4wd quit workin. if im losing vaccuum, the hubs should be engaged but they're not. i know i have to fix the leak, but why did the grindin stop if i still have the leak and the seals are holdin at the hub? sorry for the book.

 

Did you change the solenoid yet? If not you need to do that first. My hub held vacuum too but it didn't work. The teeth were in good shape too. But you need to change that IWE solenoid before you do anything else. You could have 4x4 working in 10 minutes.

 

okay well after further investigation i'm almost sure the solenoid is bad. the line isn't leakin i just had a faulty plug on the other end of the line. now here is the kicker. in 2wd with the vaccuum hoses pulled off, the axles turn, so the hubs are engaged. the whinin sound stopped which typically means the actuator is gone. i have a bad solenoid so why are the hubs engaging but no more squeeling sound? they're not bad if they're engaging and turnin right? can the solenoid mess up and do reverse which sends vaccuum to the hubs at all times vs takin vaccuum away?

 

I did the same thing on mine when I was fixing it. If you have the hoses off the actuator your 4x4 wont work, point blank. Change your solenoid like we have said for the past 3 pages. Then change your actuator out. I highly doubt your hub is bad as I posted previously. Many of us here have been in this spot and we know this problem when we see it. Are you not wanting to spend over a certain amount of money on this? Trust me when I say the actuator is easy to change out and its not that expensive.

 

well really just tryin to understand. but no i don't want to spend too much money because the truck is sold once i fix the 4x4.

 

It wont be over $200 bucks. Get the solenoid and actuator and replace them. Then say goodbye to your truck.

 

well i changed the solenoid and the actuator. still no 4wd. in 2wd it has the hubs engaged like the new solenoid is bad. i know this because with the old solenoid the hubs would stay disengaged. why would the old solenoid send vaccuum if it was bad. is there anyway to bypass the solenoid to see if its bad?

 

Hmm I'm not sure. Are all the hoses hooked up properly? And are they leaking at all?

 

the line must have had a little trash in it. shes working like a champ now. thank you guys for all the help.

 

You got it man thats what we are here for. Are you getting another truck or moving to something else?

 

deff. another truck. looking at a 4x4 dually. need somethin i can put a weldin machine in the back of. now just gotta get the weldin machine fixed.

 

wingman4, did you ever find out what's up with the 4x4 in your Expedition???

I have the same problem in my 2001 SuperCrew....you described it down to a T.

 

Well...got to the source of my problem, the vacuum actuator on the front axel is bad but there was still the grinding metal problem in my transfer case. My brother-in-law and I pulled the transfer case out...broke it down and discovered that the lock-up hub assembly was cracked and half of the teeth were ground off so it would go into 4x4 until you broke traction then it wouldn't work and just sit there and grind in the T-case while your rear tires spin. Not sure which came first the T-case damage or the actuator failing but they are both related as far as timeline is concerned.

Now I just have to track down the parts, this is gonna be fun...NOT.

I'll post more when I find the parts and get it back together.

 

try the vacuum control solenoid, its cheap and an easy part to fix. its located on passenger side firewall.... put the truck up on jack stands and turn the 4wd button on, you should immediately hear it engage of disengage if you have the solenoid jumped. That is exactly what happend to my 04, problem fixed in 15 minutes! good luck

 

T-case is repaired and back in, vacuum actuator (on the front axle) is replaced and she works like a dream now Boys! Thank God (and my brother-in-law, the heavy equipment mechanic). The problems were specifically...the vacuum actuator was rusted inside and would only move the shift rod about half way. Inside the transfer case a part called the "lock-up hub assembly" was cracked and the teeth were ground off (thus the grining metal noise inside the T-case) and the T-case pump was worn out (and replaced). Hope this helps others with the "4x4 system says it's working but there is a grinding noise in my transfer case and the rear wheels just spin when I'm on a grade" problem.