The Back Story:
So Ive been trying to track down a deep sounding vibration (like a humming) that I now have after the idiots at Town Fair Tire broke something. When I'm in drive at low rpms (40mph is when I hear it the most) and under engine load, I am getting this very deep but not very loud vibration (that defiantly wasn't there before). It's almost hard to hear but I knows its there and I feel stupid taking it back to the dealorship to have them look at it.

Last night I'm playing around with the 4x4 trying to see if it would make any difference and i put it in 4x4 Low and I get this loud ratteling noise that appears to be coming from the trasnfer case but I can stop the noise by putting my hand over the, what i think is the, engagement motor. This is when I noticed that the 4x4 front end doesen't seem to be disengaging the hubs.

Now to the question:
What exactly on the front end disengages, is it the cv joint at the wheel or on at the axel? When I had it jacked up (and the truck was off) it appeaed that the front end 4x4 was engaged because it was turning all the way back to the transfer case. Ive been reading on this site about the IWE system and it sounds like thats normal the truck should be running for it to create a vacuume and disengague the hubs, correct?

Thanks Everyone
--Ben

 

Correct, your hubs are engaged when the truck is off. What actually locks and unlocks is a ring with a gear on it right behind the wheel bearing on each front wheel. There is a double vacuum line connected to it. It locks the end of the front axle to the hub. I dont know that you problem is a IWE one since you can feel the vibe in the transfer case and make it stop when you put your hand on the switch motor. But what you can do to eliminate the IWE system is read the following link and get a good vacuum guage/tester and follow the testing procedures and check your lines and IWE's.

https://www.ford-trucks.com/forums/8...then-some.html

 

Yeah i just went out and check that when the engine is running the front end is disengaged and it was. I'm wondering now if maybe I do have low pressure and its causing intermittent engagement. I was just getting some grinding but when I would speed up or slow down it would go away.

Thanks xjcamaro8 I did read that post and it was definitely helpful.

 

Try rigging up something that will show the vacuum pressure that you can watch while driving, you will be able to tell definately at that point if the vacuum drops at or below 5, while driving.

I put a T fitting in the line after the solenoid and connected a long chunk of hose out from under the hood and in through the passenger window and hooked the guage up to it to watch while driving.

 

Will do any idea where i can get a vacuum pressure gauge? NAPA?

 

NAPA should have one. Usually its a vacuum bleeder/guage kit, I got mine at Advance Auto Parts, but im sure NAPA would have one. They would have some fittings and bulk hose as well. And whatever you do make sure all the connections you make are air tight. use a little silicone on the fittings to make a good seal. If when testing you see your vacuum fluctuate with RPMS then you have a leak somewhere. And at that point you need to start at the hose coming off the engine and work your way down to each wheel testing all hoses, check valves, and vacuum box. Good luck.

Its not hard once you start looking at stuff and figuring out what is what.

 

on my '05, both axles are locked to the wheels all the time. I had it jacked up tonight and with the truck running or not, if I spin a tire......the axleshaft behind it spins too. I have no idea how long they have been like this. I figure it is unlikely that a have a leak in each line, so where do they come together (control box/valve?) what's common to fail? where do I start guys? thanks
On a side not, the truck drives fine, no noises, the 4x4 works as it should. I did not think to look up and see if the shaft to the T-case was spinning.... it must be right? that can't be good.
I will go back and search the forums now. I just wanted to throw this out there.

 

I just read XJcamaro89's great post on how the system works. I am going to check my vent lines first off tomorrow. sounds like I should be able to blow (by mouth) air up through them if I umplug them off the IWEs. the vent is the smaller line right? my truck has never made a noise. and it's possible that they have been engaged for 50,000 miles.

 

That's a bummer, probably quite a few gallons of precious fuel was wasted turning all that equipment. I just dropped my truck off at the dealership, it's a full on grinding noise now. Hopefully it will be covered under the Ford extended warranty.

 

Framingham Ford just called me said some shield was rubbing against the exhaust (I have my doubts) and then they tried to tell me my 3 week old (brand new Toyos) tires had wear on the inside indicating an alignment problem. WHAT?!?! How is that even possible...lol. I the tires aligned when they put the new ones on, they even gave me the computer printout of the exact mesurements of the alignment.

never buying a car from them.

 

my mpg dropped about 15% last fall when I went with a slightly taller tire. unless the hubs crapped out at that time, maybe, then I noticed no loss in economy. again, no foul sounds, going out to look it over more now. I was able to visually inspect the lines this a.m. they look to be intact, up behind the battery, to intake and down to box and hubs. I have a warranty as well (but aftermarket) so I will not be going to buy a vac tester, I just did not want to take it in for a loose hose or what not.

 

Ok, so far I have located a nice area where the vac hoses contacted the manifold and burned off. I cut out two 6" sections, but one is just the vent so that can stay short. Ford gets $65 for a new hose harness so that's not to bad, should be easy to swap it, it comes complete with the check valves. I'm off to Lowes and autozone for now though to see if i can repair it with plastic line of some sort and brass nipples maybe just long enought to see if once all intact that the hub things do indeed release. Perhaps it is the same ID and OD as that plastic oil pressure or airshock line some guys use. I'll check, any suggestions? I have vac up to the burnt off point, as verified as being pressed against my tongue as the truck was started. redneckwho?.
sorry for the thread hyjack headsox.

 

I just went to the local NAPA and bought a bunch of bulk vacuum line and fittings and made my own lines from the intake to the solenoid to the box to the wheels, and i didnt run them where the stock ones were, i ran them where i wanted them just in case i needed to get to them later. Just a thought.

 

The local autozone and advance stores had nothing. ?. they both tried to give we windshield washer hose that I believe would collapse under the vac. I hit Lowes and have it spliced together with a piece of heavy nylon tube right now, press fit together pretty good and snug, I smeared it with RTV and blacktaped it. I will let it dry tonight and see if it works in the a.m. if the IWE's work I will make the drive to Napa or Fishers and get the correct parts for a better fix. if the hubs do not disengage and I have good vacume to them ( I believe I will) then it will be off to the dealer for a warranty repair, I hope. thank you.

 

Sounds good