A while back on 12th and 13th gens, there was, and still looks like, a rash of pinion bearings being incorrectly installed at the factory. Many guys kept blaming the IWE system for the grinding. Worse come to worse, it could be both.

 

Here is the latest update. We grounded the solenoid to a nearby ground which basically applies vacuum at all times and makes the truck a 2-wheel drive. I have driven it about 150 miles with no issues. We can now know that it's not lack of system vacuum causing the issue, but something on the electrical side. We are going to check the wiring that leads to the TCCM to see if there is anything that looks damaged, and may overlay a wire to see if it works properly like that, It seems we have narrowed it to either a bad wire, or a bad TCCM.

 

Please let us know the outcome. Always good to have something else to test before condemning hard parts

 

Back to the drawing board. Thought we were getting somewhere but now right back to where we started. We load tested the wire that we grounded on the solenoid, and it tested good. We were really leaning towards the TCCM (transfer case control module), so for $100 at this point it was worth a shot. Hooked everything back up correctly with the new TCCM installed and programmed and headed home. Made it 35 miles home fine. (It's done that a few times) Jump in this morning and about 1.5-2 miles down the road....the dreaded grind. Click into 4x4, it goes away and didn't do it again for the remaining 33 miles of my trip. At this point we are running out of ideas to even try. I keep going back to the fact that its vacuum, but when the solenoid was permanently grounded the system applies vacuum at all times and there was no issue.

Does anyone have any other thoughts on this? What are we missing??

 

[QUOTE=1forford;21637826]Good day fellow Ford folks. I come today with piles of frustration and a little bit of hope that someone has been where I am right now. I have read these threads for hours and can't find anything else to try. My daughter's truck is the culprit. 2019 F-150 XLT 3.5. It has a level and 33x12.5x22. The level and wheels and tires were installed, and about 1 month later we started with an IWE grind. We have been trying for about 2 weeks now to get it resolved. Little back round.... I work at a Ford dealer in sales, and the truck is being worked on by a senior master tech. We have replaced the check valve, both IWEs, and both hubs. Swapped the solenoid and the vacuum manifold (not the correct name) with a known working truck. Smoke/pressure tested all lines per Fords pinpoint tests. All of this to have the exact same issue.

The truck will make some trips with no issue. Other times as soon as its out of the half mile warm up strategy it starts to grind. Shift into 4x4 or let off the accelerator and the noise will stop. Sometimes it can be driven 20 miles and then just at random it will start grinding.

Anyone have any thoughts or ideas for me? Anyone have the same symptoms and found some strange fix that took care of it?

I appreciate any help here. My daughter really wants her truck back![/QUOTE
I think the IWE actuator is succeptable to intermittent failure when driven on a rough road. I suspect the splined shaft relies on the IWE iis the suport of the front axleshaft in 2WD as the vacuum is turned on releasing the spline from the front hub. I only notice a failure when driving on a rough road and almost never on the highway as long as I don't hit anything. when the vibration occours the vacuum actuator can't reseal.. Don't forget the vacuum holds the spline off the hub and in 4WD the vacuum actuator is vented to achieve 4WD. I think you can put the front end on jack stands and find the vacuum that it takes to pull the spring in on the spool at the hub by spinning a wheel while increasing vacuum with a hand pump. This makes sense as that would explain an intermittent problem. Also the spring is stronger the further it is colapsed so a 3 or 4" vacuum might get into the location where the tip of the spline comes in contact making noise and grinding on the hub spline without actually engaging.

 

Two screws and a tie-wrap

Resistance is Futile!

 

What parts have they replaced with the IWE's. Did they do the entire bulletin? Did they replace the vacuum lines to both sides? The TSB only lists one but you need both side. And Did they replace the one way check valve that is VIN specific? I'm going to attach the TSB parts list

 

Base part # 3C125 is what you need 2 of. These say only if necessary but if you half *** it you have come backs. I think only once have I not done wheel bearings and it hasn't come back. Always at customer request to save them money. I no longer give the option since they're always pissed they have to spend more

 

Just eliminate the vacuum and be done with it. Mine goes in and out of 4x4 instantly now. No more grinding, popping, or other weird noises.

 

Isn't fordtechmakuloco reporting a lot of front dif failures now, also? Is that related to full time IWE?

 

If it's any consolation, I was talking to a friend the other day with a Chevy 1500 that uses an electric IWE. More or less the same issues.

 

Same thing with the late model F150s. They're electric, but the issues persist.