my front hubs, which I think are controlled by air, have been giving me fits for about 6 months. Am I stuck with a factory only replacement ? I'm assuming its the hubs. I lock it in 4wd and when I go back to 2wd, I get this buzzing noise, which sounds like its coming from the front end. As soon as I put it back in 4wd, it goes away. It looks like they are vented. How is moisture NOT supposed to get in ? This truck sat for about 1 year and was only driven on the weekend. Everyone tells me this is probably why they went bad ( sat outside). If I need 4wd, I have to engage it about 1/2 mile before I need it. If I dont, I get this LOUD high-pitched popping in the front end.

 

The hubs are operated by vacuum. Moisture getting into them shouldn't be an issue. Check all the vacuum lines.

Does the truck malfunction or make any strange noises after starting it and driving it in 2wd only? Or does it do this only after switching to 4wd? The reason I ask is because the hubs lock themselves when you turn the truck off. Then un-lock when you start it. If this was simply a matter of the hubs not unlocking.....you'd have this problem every time you shut your truck off and re-started it.

Try this, with your truck not running, see if you can rotate the CV's by hand. They shouldn't rotate. Then start your truck. They should now be unlocked and able to rotate freely. Now shift it into 4wd.......they should lock again. Shift it back to 2wd and they should unlock. Now turn your truck off and make sure they lock.

Lemme know how that works out.

 

I had the same problem. The part that Ford calls the actuator has a spring that seals the rubber boot. The spring had a kink in it because I damaged it while installing my lift. They do no sell the spring only. I had to buy a new actuator which was 100 bucks. Hope this helps.

 

thanks hillbilly delux,
I did your test. Its been at least two wks since I've used 4wd. I jacked the front end up ( both wheels). the engine was off, selector in 2wd. the wheels would spin, but I noticed the front driveshaft was turning. from behind the front left wheel, I could hold the front driveshaft. when I spun the wheel the pass side would turn the opposite direction. I let the jack down so the pass side tire was on the ground. then the drivers side tire would not turn as long as I was holding the front driveshaft. so it seems that what you stated is true as long as someone hold the front driveshaft from turning.
let me back up for a second. when I first jacked the front end up and spun the pass side wheel, I did hear the buzzing sound that I mentioned in my original post.
I then started the truck, still in 2wd and checked both wheels. each side, while the opposite was on the ground, would spin even when I was holding the driveshaft. I then put it in 4wd and each wheel would not turn, provided the opposite side was on the ground. this senario was true when the truck was running and off.
but there was one thing that did puzzle me. I put the truck back in 2wd, turned it off. I spun the drivers side wheel forward. it probably rotated 5 or 6 times. I then spun it backwards. it rotated maybe twice, the made a clunking/thumping noise. I assume this was the hub locking back in. was this delay normal. I still think that my problem is in the front hubs. it seems like they are either not engaging or disengaging all the way. I think the pass sied hub is the worst.
LIke I said on the 1st post, after using 4wd and the going back to 2wd, I get this loud buzzing sound from the front end. it is most noticeable around 20/40 mph

 

i had the same problem i just replaced my front hubs and it doesnet do it at all

 

whats the cost to replace the front hubs?

 

They hit me for $337 total at stealership to replace left front. OEM part was $209.

Tech says they work on vacuum pressure holding them in or out? until you use 4WD then vacuum off and they engage is maybe why they fail so often.

I had a loud squeal like bad brakes until 4WD engaged then quiet.

If you wait too long you will have to replace the spline also.

 

I just started having this problem in my 2004 F-150 last week - coincidentally when I moved to Phoenix. Could the very hot weather have anything to do with the hub not getting enough vacuum pressure? I get a "ratchet sound" (like the sound the sprocket makes while coasting on a bicycle) just after I start up and only from the FR wheel. Putting the truck in 4WD makes it stop. Back into 2WD and the sound comes back... Your help would be appreciated.

 

Ok I know this thread is old, but your little test saved me $1500 no joke! I went to the dealership because I thought my truck was stuck in 4wd, they didn't even look at it and started telling me the things they needed to buy to fix it. I didn't think anything of it. So I come home and find this thread with Hillbilly deluxes test, try it, and find out that my truck isnt in 4wd, infact it is just fine. Now im not afraid to use 4wd so much. You can't possibly understand how happy I am right now.

 

I have a 2004 F150 it started grinding about a year ago and since then i have replaced the IWE solenoid and that didnt help so I tested all the vacuum lines held good vacuum. I ended up having to replace both IWE actuators. The other night I was driving and needed 4x4 so I locked it in 4high and when I put it back in 2high now the noise is back and wont stop. Could the vacuum box or vacuum line goin to the engine be my problem and if so how can I check it?