You both might need to pull the wheels and hub assemblies off and clean them up and apply some new grease. Could be lots of dirt in there not letting the shafts engage. First off though see if you can move #4 axle shafts below in and out by hand with the front end lifted and the engine off. (so you can spin the tires for the teeth to align) It should slide back and forth fairly easy with the teeth noticeably engaging into the hub. If they don't then the axle shafts could be seized up internally and will need a grease injection done or replacement.

I wish I had a internal break down of #4 but that a complete part in from what I can tell.

Oh before I set you up for failure get some new seals for the wheel hubs. They are like $4 each from what I recall.



Here's another view if the front axle going into the spindle and wheel bearing hub.



On a side note TN-F150 could you resize your sig? I get a finger cramp trying to scroll though this one page.

 

Impact, thanks for the information. I'll try out the axle shafts tomorrow to see if they slide in and out without much effort. It just sucks to be having trouble like this, as I bought this truck from an 82 year old man who said he'd never had it off the road, so I thought this stuff should be trouble free. I've always liked Ford's trucks (had a Ranger the last 14 years that was my daily driver), so I automatically went to the F150 when I moved up. I might have rethought that if I'd realized these have so much trouble with these IWE's , lol. It's just now turned over 40,000 miles, and there's no telling how long this stuff hasn't worked. I doubt if the guy I bought it from even knew that they didn't work. Back to the task at hand and just to make sure I'm following you correctly, what you're saying is, if I can slide the axle shafts in, while turning the front wheel, I should be able to make the axle shaft/IWE's slide into place and engage the front wheel/hub assembly (basically engaging 4 wd manually). If not, I may need replacement axles and/or IWE's as well, correct? I was under the impression though, that with the axle shaft being fastened to the differential on one side, and then fastened to the hub on the other side by the spindle nut, that it wouldn't move except for when you were turning. I had it in my mind that the IWE was the only moving part in the hub area for the 4 wd system, moving by way of vacuum or the internal spring. Sorry for my bit of confusion here, but this is my first go around with a troubleshoot and repair of the 4 wd system on anything. Sorry to say, my wife's Envoy has been trouble free for 100,000 miles now, and she probably doesnt' engage the 4 wd, but about once every 6 months.

 

No need to apologize, it's all good info and everyone can see the different issues. The hubs lock with no vacuum so in your situation, if say the truck was on 4 jack stands and running in drive in 4wd, the wheels should all be turning (of course ALL would be depending on lockers or not etc etc). The front doesn't have a locker so if you have one actuator not working, the front is dead in the water. Due to the diff type, it will send all the power to the least resistant side. If both axles are spinning and neither wheels are, you may check the vacuum portion of the system, but it could be both actuators too. Mine went one at a time but about 1 week apart, so my bet is they both were damaged and probably at the same time. On your last question, replace them. Nothing serviceable about them unfortunately.

Also with the short time of ownership, these actuators could very well be engaging but if the previous owner drove them the the point of completely rounding the teeth there would be no noise for you and no engaging either.

If I may jump in here.

The axle while installed on the truck will not move in, out or any way. The only part that moves is the gear in the actuator between the hub and axle shaft and once the truck is turned off and lifted off the ground, the hubs should be locked in, if working correctly. But once the axle is installed and/or tightened from the outer nut it is basically drawn up tight to the hub gear. The actuator gear rides on the axle shaft gear while in 2wd and when switched to 4wd or the truck is shut off, the actuator gear slides to make the axle gear and hub gear joined as one basically, engaging the front wheels. One last thing, besides the differential the axles are probably the strongest part of this system so that would be my last concern unless you have the typical CV joint popping noise indicating a bad CV joint. These things a pretty much bullet proof as long as they stay greased and no tears in the boots that would allow grime in and eat *****/cages/cups. Your assumption of the only moving parts above (in BOLD) is correct.

Also, manually engaging/disengaging the actuators could only be done with a vacuum pump. There's literally no way the engage anything by hand with the system assembled.

I received another PM today and wanted to post it here as well, regarding re greasing things.

I am only talking about adding new clean grease to the hub gear, axle gear and inner teeth of the actuator gear. The internals would not be serviceable. The outer spline of the axle shaft where it goes THROUGH the hub could be greased I suppose, but would serve no purpose since it is stationary once the axle is installed. Also, I am meaning silicone BASED grease not to be confused with silicone itself. That would create a whole new set of problems.

If you look at the first page at my pics you will see both the axle gear and the hub gear. The actuator gear slides back and forth across the two to make them one gear when engaged. The axle gear has a slight dish in the front face (not sure the pic shows it) and when installed and it fits against the rounded part of the hub and making one wide gear. The actuator rests on the axle when in 2wd and slides across both when switched to 4wd, when vacuum is removed or when the engine is off.

 

Really!? The pic isn't that big. What size monitor do you have?? The pic is only about 480x360...

 

Interestingly, the pic above omits the actuator but could be because this is torque values diagram.

The axle is made up of multiple parts and although serviceable would require the boots to be removed to re-packed the joint with grease and an "injection" would require a hole and defeats the purpose of the boot. Also, if we are all on the same page, there are no seals at this level of the front axle/actuator. There may or may not be on into the hub assembly but not as far as the actuators and outer CV joint are concerned. I have not had the hub assembly out of this model but more than likely would only have a rubber o-ring on the hub assembly to seal it in the knuckle.

 

I'm new to this forum, but have found a lot of good info. Your post on IWE's is great. My problems have gone from vacuum leaks due to busted lines to the solenoid and now the IWE's! BUT get this, I knew the IWE's had been going bad so I've been driving aroung in 4hi mostly. Here's the weird thing, now it is jumping out of 4hi. Now mind you it has been way below freezing here and what I think has happened is the 'leaky' actuator have ingested enough water from slush melting into the hub that it is all frozen now and it won't do anything. Stuck in 2hi without vacuum in the lines!

 

Glad it's helped. The actuators can only get anything in through the vacuum port on top and that would have to go through solenoid first (were most of the early failures were caused from before the redesigned solenoid). The Winter definitely plays a major role in these things failing.

Also, if you are driving around on roads that have been cleared of snow and ice and don't give the system room for slipping you will do damage from that as well. You should never drive in 4hi or lo on dry pavement. (If you are??) These CAN get snow and ice build up near all the gears and could cause them to freeze engaged or disengaged. Have you fixed the vacuum line and solenoid? I wouldn't tear into anything till those issues are fixed or you will end up doing them again.

Constantly driving in 4hi with one failing can cause the jumping out too. It will catch then miss over and over till it has no teeth left on the gear.

 

Thanks for the info. I was unsure whether the hubs were sealed or not so I was thinking that the moisture was getting in there. If that is not the case, then since I have updated the solenoid and I don't think I have a vacuum leak anymore, I'm pretty sure my problem was a bad check valve because the only time I had the ratcheting noise before was on the gas and that must have eaten the gear up. It went one trip home going in and out of 4hi and then no 4wd. So, like I said, I'm looking at replacing the checks, testing the vac lines and replacing the passenger side IWE.

 

Thanks for the further information TN-F150. I did try to turn the front wheels with the truck on jackstands, and it still didn't turn the front axles (half-shafts) with the truck turned off. When on jackstands (all 4 wheels), and in 4 wheel hi or low, it will turn the front driveshaft, and axle shafts, but you can hold either front wheel and it makes no difference, it's not trying to lock or turn them in any way. With the info from this thread, I went ahead and ordered both new IWE acuators from Tasca Ford, as well as a new IWE solenoid, as my truck still had the old style, non-hooded solenoid on it. My half shafts still look great, no tears in the boots, no grease leaking from the clamps or anywhere else, so I figure they should be good to go. I did check vacuum on the end of the lines with the solenoid connected and the selector in 2 Hi, and it pulled around 18inches of vacuum on my guage, so I assumed the lines are alright, as I can't see it holding that well if the lines were damaged. I did check with my local Ford dealer, (who is normally terrible to deal with anyway, for what it's worth), and they quoted me $900 to do both front IWE's and a new solenoid, using my existing vacuum lines. They then quoted me $400 for the 2 actuators, and the solenoid. I bought all of the parts from Tasca, shipped for $220. Thanks again for the great thread and the install instructions, I look forward to getting the parts in and getting this truck back operating like it should.

 

Sounds like you're on the right track. For the record, I'm betting the dealer was quoting hubs for the $900 because the IWE (Integrated Wheel End) and actuator is actually the same part. I was quoted $500 for one side for a mis-diagnosed HUB by my local dealer. Of course, that's when I took matters into my own hands and researched this problem only to find out they were quoting the hub. That of course would have not fixed the problem.

Good luck and reply back when you get it fixed. If you run into any issues, PM me and I'll get an email. I'm always a pocket away from email. What would I do without technology?

 

Technology can be great, I've learned that with the internet, you can pretty much fix just about anything if you're a little mechanical. I saved $550 last year by fixing my Mitsubishi big screen, found the problem online, went to Radio Shack and bought 6 capacitors for $11 and soldered them in, been working fine for 14 months since. Local TV shop came out and looked at it, told me $550 to fix it... I wouldn't doubt that they quoted me for the hubs and all, but nothing surprises me with them. I've been around with them numerous times over a couple of vehicles that I've owned. They tried to not cover a tranny under warranty on my old Mustang because they said that I was "hotrodding" it, and that's why it broke. Nevermind the fact that it had been in the shop 9 times for the same transmission issue, the first time of which was at 1400 miles. Then when they called to let me know that it was fixed (they rebuilt the trans under warranty, but only after I went to Ford Customer Service), as I pulled into the dealership, they were towing my car back in. The transmission failed as their tech was test driving it, so I politely asked them what kind of "hotrodding" their tech was doing to break it, lol. Nevermind that it had been at their dealrship for 3 months at this point, and I received no rental car. Oh well, enough ranting, all of my truck parts came in today, so I will probably tear into it tomorrow as I'm off work. I'll report back when I get it buttoned up. Thanks again for all the information, it's been priceless.

 

Update---as of this morning, the truck is fixed. Ended up not needing IWE's replaced, due to my quick judgement of what I thought was wrong. As it was, I checked vacuum the other day at the IWE's with a vacuum guage, and the truck RUNNING. So, in 2 wheel drive, it was holding 18-19 inches of vacuum, change the switch and it fell to less than 6 inches of vacuum, so I assumed that the IWE was stuck disengaged. This morning, got up early to dive into it. I pulled the wheels off, and when I went to disconnect the vacuum line from the IWE, it hissed... I thought to myself, the truck's not running, and hadn't been for 15 minutes at that point, so there shouldn't be vacuum on that line. I grabbed the front spindle and turned it, and sure enough, the half shaft turned as well, meaning the IWE locked in. As it turned out, my solenoid had failed to where it never opened the IWE vacuum line to bleed off the vacuum. It was holding manifold vacuum all of the time, and then when I turned the truck off, it was holding vacuum to the IWE's from the resorvoir box in the fender. This was what caused my initial mis-diagnosis, because I thought automatically that it should default to 4 wheel drive and IWE's locked in once the truck was turned off. I had tried to turn the front wheels with it jacked up and turned off, and the half-shafts didn't spin, so I jumped to the conclusion that the IWE's were just stuck and possibly the springs were bad in them. So, I ended up replacing the solenoid, checking both IWE's and everything works great. We've still got a little snow on my side street, so I took it down the road and tried it out and works like it should. So, in short, if you don't get any noises from the IWE's when trying to go into 4 wheel drive, but you're 4 wheel drive doesn't work, start off by checking the drivetrain with the truck on 4 jackstands to make sure that everything else is running correctly, then check the vacuum line to see if it's holding vacuum even when the truck's turned off....

 

Well I wish I had found all this very usable info a while ago; turns out that both check valve were bad. Due to the old style solenoid, the whole system has been full of rusty water, which is evident from the residue. So as soon as I can get to the dealer to buy the $4.00 vacuum check valves for $20.00, I will see if I still have a problem. I bought one IWE from Tasca because the passenger side is the only one that has ever made any racket and so on. I still think that it could be possible for the contamination to come from the hubs if you had a seal fail and the actuator got torn up to the point that the bladder leaked.

 

I just started getting the front axle whine on the passenger side of my '06 SCrew. I installed a leveling kit about 3 months ago and thought maybe that had caused it. At the moment, I'm not having any problems going from 2WD and 4WD and back.

A couple questions:

1. Did any of you with this problem install a leveling kit and notice this after installation?

2. My truck is still under warranty. If I take it in for warranty work on this issue, the dealer is probably going to blame the leveling kit. Do you guys think I should take the leveling kit off before I take it to the dealer?

 

I put in the 2" AutoSpring leveling kit but I highly doubt the two are related. Mine was in for over a year before I had the problem. There's just nothing to do with the IWE's that could even remotely be connected to the leveling of the suspension. I just changed both on my father-in-law's 2004 that is bone stock.

I wouldn't remove it before taking it in. If the dealer tries to blame it for the problem they either don't know what the h*ll they're doing and you don't want them touching it anyway or if it's under warranty they want a reason not to issue the claim. Either way, find another dealer if that happens.