2018 grinding noise

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About 30 miles into a 160 mile return trip from a ski weekend, my 2018 Raptor suddenly started making these grinding noises seemingly from the drivers front wheel. This grinding noise wasn't constant. Came and went. And strangley seemed to more likely to express itself during uphills.

Stopped and looked things over as much as possible but couldn't find any issues. At this point we were fairly remote, outside of cell service, so we decided to press on. Made it about 35 miles to the next small town. Sunday afternoon, no services available. Futzed around some more, the grinding noise became less prevalent, and decided to try the 60 mile leg to the next larger town, that does have a Ford dealer. Made that. And by the time we got there, the noise seems to have stopped completely. Passed through that town and made it home without further incident.

Wheel bearings were a prime suspect. Jacked up the truck and tested both front wheels. Neither showed any signs looseness, wobble, or chunky rotation. Doesn't appear to be a wheel bearing.

I've now discovered Ford's IWE system. With IWE, Ford uses vacuum to engage/disengage the front hubs.

Anybody out there seen an IWE problem lead to grinding noises in the front wheels?

 

[FordTechOne]

As you mentioned, sounds like a vacuum issue to the IWE. The easiest way to isolate it is to engage 4A; if the noise stops, it’s 99% IWE related. The IWE system is extremely simple, but many times it’s misdiagnosed.

While pulling a hill, the engine is under low vacuum. Therefore the system is relying on the check valve and the integrity of the vacuum hoses and IWE diaphragms to maintain vacuum and keep the hubs disengaged. Any leak in the system will cause vacuum to bleed down, and the IWEs will begin to partially engage, causing the grinding noise you’re hearing.

The system can be tested with a basic hand vacuum pump to isolate the leak/issue.

 

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This raises a question. Eco boost engines are turbo charged which means there may be no engine vacuum. is there an explicit vacuum pump?

 

[FordTechOne]

This raises a question. Eco boost engines are turbo charged which means there may be no engine vacuum. is there an explicit vacuum pump?

Turbocharged engines still have vacuum just like any other engine, as long as they’re not in boost. On Gen 1 3.5, a cam driven vacuum pump was used. On Gen 2, the system draws engine vacuum, but is supplemented by an aspirator assembly (Venturi) to maintain vacuum under all conditions.

 

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Thanks for the info FordTechOne. You've been very helpful.

Next question is, what happens when the hubs engage at an unexpected time? I once owned an old Willy's Jeep. You could engage/disengage 4WD while moving as long as you were going in a straight line on a smooth surface.

Don't know much about the much fancier Raptor 4WD system. I don't know if the prop shafts are floating or under power. if it were a system like my old Willys, engaging/disengaging the hubs on smooth flat roads would hardly be noticeable. Apparently, the prop shafts need to engage/disengage the hubs at appropriate times. Or maybe the problem is that its a partial engagement.

And, I've probably abused my hubs now. How do you inspect these things and are they part of the powertrain warranty?

 

[smurfslayer]

You definitely don’t want to have partial IWE engagement for any prolonged period of time. If you hear the grinding, go to 4a instead of 2h. economic difference is negligible. I’m almost ALWAYS running 4a and have been since 2017.

There are a lot of online IWE ‘horror stories’ lamenting costly repairs. If you catch it quickly and address it, you can get by with a $9.00 repair - replace the check valve. Or maybe a hose has gone bad, another inexpensive repair. Again, the trick is to listen for it and fix it if you suspect IWE issues.

Because neglecting the noise is how you cause expensive damage.
OP being on here asking the questions shows care and concern that likely inoculates them from stupidly expensive repairs resulting from ignorance or neglect.

I know there’s a ‘start up / cold operation’ strategy that I believe leaves the hubs engaged for the first few minutes/miles as the engine warms up, @FordTechOne can more eloquently speak to this, but once out of that, if you’re in 2H, the hubs are disengaged --with vacuum--. That is, absent vacuum, the hubs are engaged so that if you had lost vacuum, the truck would fail over to hubs engaged and you still have 4a, 4h and 4L options.

HTH

 

[nikhsub1]

Leave the truck in 4A as mentioned - the most likely culprit is this $15 part, the IWE check valve. Takes 5 mins (or less) to replace. Sits on the brake booster. Here is a pic of the part number

IWE check valve storage

Got a IWE check valve today as a backup. Stored under the console in case of emergency. I guess that’s like an extra coil pack in the glovebox if you got a VW/Audi lol

www.fordraptorforum.com

 

[FordTechOne]

You definitely don’t want to have partial IWE engagement for any prolonged period of time. If you hear the grinding, go to 4a instead of 2h. economic difference is negligible. I’m almost ALWAYS running 4a and have been since 2017.

There are a lot of online IWE ‘horror stories’ lamenting costly repairs. If you catch it quickly and address it, you can get by with a $9.00 repair - replace the check valve. Or maybe a hose has gone bad, another inexpensive repair. Again, the trick is to listen for it and fix it if you suspect IWE issues.

Because neglecting the noise is how you cause expensive damage.
OP being on here asking the questions shows care and concern that likely inoculates them from stupidly expensive repairs resulting from ignorance or neglect.

I know there’s a ‘start up / cold operation’ strategy that I believe leaves the hubs engaged for the first few minutes/miles as the engine warms up, @FordTechOne can more eloquently speak to this, but once out of that, if you’re in 2H, the hubs are disengaged --with vacuum--. That is, absent vacuum, the hubs are engaged so that if you had lost vacuum, the truck would fail over to hubs engaged and you still have 4a, 4h and 4L options.

HTH

Since his truck is an ‘18, it may not have the revised cold start strategy unless the TCCM was updated. The update was implemented in production in September of 2018.

 

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Truck was built in February of '18.

Don't know what a TCCM is. I did have the phaser update installed. Which had a side effect of dramatically reduced the shifting into gear clunck when its cold. If the TCCM update is simply firmware, it may have come along with the phaser update.

 

[Macdaddy]

You must be new to this forum. It’s seems there is an outrages number of us who’ve experienced the rediculous IWE issue. It s almost like it’s a raptor initiation you have to go thru. My initiation was at mile 12 off the lot. It’s a sickening feeling to have a brand new $75K truck to sound like something’s in the garbage disposal. Anyway, if you didn’t “grind” a whole lot then probably no damage.