RadioMan

2010 F-150 4X4 with less than 16k and two months out for powertrain warranty. Fords better idea on its 4X4 system is; when engine is off, vacuum is lost (normal) to the transfer case causing system to put itself into 4X4. When engine is re-started if the system switch was in 4X2 when shut off it must now put (vacuum) itself back into the 4X2 mode.

What happened to mine was, I was getting a whining noise when I'd put the truck into gear (4X2 Mode). I'd stop as soon as I heard something was wrong and I was never going any faster than 5mph. I would try and go again and most times it was ok. But after a few times of this I thought I had better get this looked it.

I was VERY lucky. Ford just called me and said it's ready to pick up. A vacuum control unit plus labor, $147.24. It *could* have been $800 plus if I would have not had anything done about the problem. The gearing for the front drive shaft within the transfer case would have ate itself up..

What the were the Ford Engineers thinking with such a stupid idea? You would think the design would be just the opposite. It TAKES vacuum to put the system into 4X4 not REMOVE vacuum. STUPID STUPID STUPID!

Guys, if the above happens to you. Get it repaired right away, like I did.

You just got to wonder where Engineers get their education! No thought process at all when they came up with this system for sure!

MCDavis

iTrader: (1)

Vacuum only controls the hubs. The TC won't engage with a loss of vacuum. So the only damage you'd see is badly worn IWEs.

RadioMan

What hubs? You may be thinking a 250 or above. No hubs on a 150.

MCDavis

iTrader: (1)

Your wheel still has a "hub", which is also referred to as the IWE (individual wheel end). This is what contains the splined portion that engages and disengages with vacuum. The "common fix" for guys that have a vacuum leak is to pull the vacuum lines, thus engaging the IWEs and dealing with the slight wheel drag as opposed to chewing up the splines....temp fix until you can solve the vacuum leak. Again, the TC is not engaged when vacuum is lost.

MCDavis

iTrader: (1)

I'll also leave you with a bit of reading from another forum. It's in the 2004-2008 F150 section there, however the system's inner workings are quite similar if not identical. A lil education on the IWE and the vacuum operation would be a good thing:

http://www.ford-trucks.com/forums/83...then-some.html

kidastra

iTrader: (1)

maybe I'm wrong but isn't the TC always engaged, which is why we can shift on the fly? I could swear when in 2wd everything is spinning under the truck, 4x4 just engages the IWE

RadioMan

I pick up the truck in a hour or so.. I will ask questions BUT I still think there are NO hubs.. All I (.)(.) when I change my own oil and filter are CV joints. No vacuum lines at all.. I've rotated wheels and see no hubs.

I'll let you know after I pick up the truck and ask questions.

Tothemax

MCDavis

iTrader: (1)

If this was true, then we wouldn't need a shift motor on the transfer case...which often locks up if much time has passed without engaging 4wd. Good idea to shift into 4wd a few times a year just to keep things well lubed.



You won't be able to "see" the hub as it's all contained within the wheel assembly. What you're thinking of are "manual locking hubs" that many rigs still use where you in fact exit the truck, turn a selector on each wheel, and get back in the truck. The hubs in our own trucks are auto-engaging...thus the vacuum pressure. FWIW the vacuum lines are small, black, flexible pvc and should be coming out of the top near the location of where the half shaft enters the wheel assembly.

You really should read the link I provided. It's VERY helpful.

kidastra

iTrader: (1)

I guess im confusing my last vehicle