mrgr8ness

Finally getting around to getting my 4x4 fixed. I think I have an IWE issue, but started poking around under the hood just in case. Looking at the passenger side, the IWE has 2 vacuum lines coming off it. One goes up to the frame rail and forward, the other goes straight up toward the solenoid, makes a hook on the end, and mine is not hooked up to anything. I am thinking this is at least part of my issue, but I don't see a fitting or tee anywhere for it to connect. Can anyone help, or provide a picture so I can see where its supposed to connect?

lewissa81

Without looking at your truck, I'd say that's your iwe vent line. It should be open. If you do a search in the forum for the vent line, there should be a few pictures to confirm that's what you're looking at.

bourgeois1269

I don't recall the vent line making a hook on the end and the vent line should be visible inside the fender well

techrep

iTrader: (1)

Take a Picture..

mrgr8ness

Wanted to follow up with feedback on this. They were indeed the vent lines. The issue I had was grinding from the front wheels while in 2 wheel drive, mostly going up hills or really getting on the throttle. 4 wheel drive in forward seemed to have only left front working, grinding in left front while 4x4 reverse, and slipping. Jacked the front of the truck up and spin the front tires while running and not running. Left side was engaged all the time. Right side would disengage, but while engaged would only make clicking sound and not lock in the cv axle. Found my iwe gears were all ground up(left side iwe gear actually broke free from the rest of the unit), along with the gears on the wheel bearing assemblies. Replaced both iwe and wheel bearing assemblies. Broke the stud off the end of one of my cv axles in the process and had to replace that too. Put it all back together and was still making slight grinding on hills. Found the vacuum check valve was bad. Caused all that damage to begin with. Most of the damage occurred under previous owner. Amazing a $5 part caused hundreds of dollars of repair. I replaced the check valve, and all seems fine now.

EBC-150

Agreed, those little parts can cause a lot of issues with this 4WD system, and usually go overlooked in trouble shooting. Depending on model year, there are either 2 or 3 check valves in the system. It is best to inspect them all and replace if necessary.

bwFX42006

Just curious, but what years have 2 check valves, and what years have 3? I'm assuming maybe 2004-2005 are different than the 2006-2008's? I ask because I just recently overhauled my entire IWE system (new IWE's, new vac lines, new cv axles) and want to make sure to go over the old check valves if I have any other problems. Seems to me that since I have a 2006 FX4 I would have 3 check valves? TIA.

jb2012

I didn't know any had 3, but here is a picture I stole from the 4x4 troubleshooting guide. mods if I need to remove it let me know, no harm intended.

EBC-150

My '05 had 3, the third located in a 'T' fitting next to the vacuum reservoir. I haven't looked at the '07, no problems with 4WD (yet). There is a very informative thread on the entire system: https://www.f150forum.com/f72/how-di...m-esof-186872/

ReaperHWK

I just replaced ALL the lines from the solenoid to both IWE's, on ebay (it's one part number).


http://www.ebay.com/itm/201441144332?_trksid=p2060353.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT
After a while these lines get brittle and crack, the new ones are so much more flexible for sure.