I'm sure this has been covered, but the previous thread I read was slightly different.

My 2018 F-150 3.5L 4x4 has had the dreaded IWE grinding sound only twice in the past year (only on acceleration, very brief instances). 99% sure it's coming from the driver's side front. No binding when turning in 2WD, no growling or humming. I pulled a vacuum on the tubing that goes to the IWE's from the solenoid and it holds @ 25, no problem. I replaced the vacuum check valve in 2022, and the IWE noise happened once in about 3,000 miles since then. Yesterday, I started the truck and drove it in the driveway in 2WD, the front driver-side CV axle was rotating, could not see the passenger side until more diagnostics are done. My plan is to jack it up and turn the wheels by hand while following further diagnostic procedures.

My question is - Is the CV axle supposed to rotate with the wheel while in 2WD, or only when the IWE is engaged - or is the IWE possibly failed? I am aware of the testing procedure for the IWE but I want to know what others think about the CV axle rotating.

Thank you for your time in reading this, Nathan.

 

I think they initially are engaged and after a few hundred feet, the pull vac and disengage.

 

The operation depends on the programming in the TCCM and if the newest TSB is performed. With the newest TSB:

This means the front CV axles will rotate for a period of time, under certain conditions. Note that if in 2WD, the transfer case is still in 2WD mode despite the CV axles may rotate.

 

Thank you, is it necessary to take my vehicle to the dealer for an 'update' to the TCCM and other systems? Pretty sure it's still programmed from the factory.

 

You may be able to just ask your dealer if the TSB was performed. It's TSB 22-2219. It's one of many aimed at the IWE noise complaints.

Note that if you have the 4A option, the TSB referenced above is slightly different. It will cause the front CV axles to spin all the time, regardless of the 4WD position. The ones without the 4A option still have IWE control but on a delay as referenced above.

 

Perfectly normal on your year truck. Yours should have been programmed at the factory with that logic.
I'm not so sure temperature affects the logic anymore, I know for sure on my '20 it doesn't.
The TCCM is programmed that on every key cycle, the IWE solenoid will stay de- energized for .5 mile, or .8 kilometer, to allow vacuum to form. At that distance, the solenoid will be energized, and allow vacuum to the IWEs disengaging them.
Yes, if the TC is in 2H, it will not be engaged.

 

There is a PID you can monitor to tell you the commanded state of the IWE system.

TCCM - Transfer Case Control Module
PID: IWE_OS - Integrated Wheel Ends Output

If it reads No, the TCCM is commanding the system to disengage the IWEs.

Note I use the word commanded, because if there is a failure, the reality could be different than from what is expected.

 

not to post steal, but is this the same on 2014 f150? I rebuilt the front end and marked the cv axles with a paint marker and noticed that they never moved for 2 weeks and recently noticed that the paint marks are in different locations now