justjimmy

I know a vacuum is involved with turning the 4WD on or off.

Does the vacuum switch the front wheels into 4WD or does it switch into 2WD?

Reason is I believe my truck trying to switch into 4WD while driving. The past few days, as I'm driving and turning slightly, I hear clicking...almost a light grinding from the front right wheel. I can feel the vibration in the steering wheel.

It's only happened a few times but it truly feels like it's trying to engage the right front wheel.

Could a vacuum line be loose or leaking?

slider911

Search IWE. Lots of posts about this issue. Easily fixable.

Steve Osborne

when engine off/ 4wd on ---no vacuum applied...2wd ---vacuum is trying to pull hub out of 4wd...clicking grinding....guys screw up on the lift kits...etc...lots of info out there...

justjimmy

Thanks. I'll search in the morning and get up under it to see if the line is loose.

Hopefully I can find some pictures.

Not very mechanically inclined.

Thanks for the tips.

Cowpig

thread about diagnosing the problem, and a link to a good youtube video on diagnosing the 4x4 system as well as DIY replacing the IWE
https://www.f150forum.com/f38/first-...essing-339689/


when you don't have vaccum (either because of a leak in the system, or because you have engaged 4x4) the IWE hubs lock at the wheels / cv shaft turns with the wheel.

when you do have vacuum you're in 2wd / the cv shafts should not turn with the wheels

justjimmy

Thanks cowpig.

Looked at the video this morning and it seems pretty easy.

It was interesting about the water in the IWE. When I go off road, there is lots of water I go through from time to time.

Also, this has only happened a few times so it's very intermittent. It seems to go away if I turn the 4WD on for a few seconds, then off again.

I have an appointment with the dealer next Friday but I'll take a look before then to see if it's a simple fix...vacuum line issue for instance.

Thanks again for the help/link.

justjimmy

Thanks cowpig.

Looked at the video this morning and it seems pretty easy.

It was interesting about the water in the IWE. When I go off road, there is lots of water I go through from time to time.

Also, this has only happened a few times so it's very intermittent. It seems to go away if I turn the 4WD on for a few seconds, then off again.

I have an appointment with the dealer next Friday but I'll take a look before then to see if it's a simple fix...vacuum line issue for instance.

Thanks again for the help/link.

justjimmy

Wow, I guess I really wanted to thank you.

Apologies for the double post.

GrasslandHVAC

I should really get off my *** and see if I have a vac leak too. I do not hear any noise or feel anything weird, and it certainly does not feel like I am in 4x4, but I get horrendous fuel economy. Maybe my hubs are engaging and the cv and front axle mass is enough to drag my economy down a couple mpg.

Cowpig

jack up the front / get the tires off the ground - start the truck and turn the wheels, if either/both of the cv shafts are turning you have a leak someplace