socal805

That is exactly what I do and it instantly stops. I told the dealer this when I brought it in. You would think they would have done something.

Hopefully tomorrow.

DemonGT

iTrader: (1)

all they need to do is unhook the vac. line from IWE and put a vac gauge on it and see if they both hold vacuum. if you have a vacuum pump you could do it yourself also.

some vacuum loss is ok but if it drops off quick or dosnt hold at all the seal is shot.

mine is like this

socal805

I understand the loss of vacuum what I don't understand is why it is intermittent. Yesterday it only happened once. Today it happened once on the way to work and 3 times coming home. I am beginning to think warmer temps might be contributing. It was 89 here today.

ConiferEric

I have the exact same problem with my 2014 F150. I have the auto mode transfer case and the problem has progressed enough that it occurs in the 4A setting as well as 2H.

Phil Long ford in Lakewood, CO hasnt had any luck diagnosingvthe problem. I agree with you that its a problem in vacuum system.

DemonGT

iTrader: (1)

there is a solenoid that could be the problem also. so if the vacuum checks out ok on the IWE then that would be the next stop. my 05 also had two vacuum check valves also but not sure how the new trucks compare to older models. the check valves were between solenoid and intake.

If the IWE is trying to engage your losing vacuum to the IWE somewhere. so you have the IWE itself, solenoid, id assume check valves and the lines themselves. find where the vacuum is going and you will find the culprit to your troubles.

CurryBob

So if the IWE is losing vacuum in the line, then it is trying to engage the 4X4??

DemonGT

iTrader: (1)

not the 4x4 just the hubs, the transfer case has its own solenoid to make it engage.

snobdds

They have been using the same vaccum powerd hub disconnect for a long time now on the F series truck (F150, 250, etc). It's actually a good system, when compared to dodge and their system. In a Dodge, if that system fails and your stuck, your stuck. In a Ford, one could just create a controlled leak and force the hubs to lock. I'll take that anyday.

The hubs are just not unlocking, which means a vacuum leak. I always start at the hub and work my way up to the vacuum solenoid to check for vacuum leaks. If none than check your vacuum solenoid to see if it is switching vacuum. If still working ok, then you have to look at your sealing orings in the hub. One of those is where your problem lies.

DemonGT

iTrader: (1)

what i did in my 05 is, i bought new IWE's but could not get them changed right away so i disconnected the vacuum line under the hood that went from the intake to the solenoid and then capped off the engine side of the line with tape. this kept the hubs locked in, that way there was no grinding to cause damage and my 4wd would still be functional if i needed it. hubs are already locked in so when you flip the switch the transfer case kicks in giving you 4x4.

do not neglect the vacuum check valves, after installing new IWE's they worked fine for about a month then started grinding on one side so i switched out both check valves with new ones and it worked perfect after that. turned out one of the check valves was shot, you can tell by blowing through them. if you can blow through both ways its shot, should only be able to blow through it one way and there pretty cheap so i just replaced both not wanting to chance the other one pooping out.

FordService

Sounds like it's time to loop in your regional customer service manager, ConiferEric. Please send me a private message with your full name, VIN, current mileage, servicing dealership, and best daytime contact number; I'll get started right away!

Brittany