Hey guys new here. My 2018 f-150 makes intermittent ratcheting sounds when you first start driving like it’s trying to go into 2wd but after a bit it gos away. Driving up a snowy road the other day was in 4wd and when I took it out and put it in 2wd it was a steady grinding for about 10 minutes (couldn’t stop on icey highway) anyways I checked for vacume at the hubs and the hoses up top and it seems no leaks and holds pressure. Reads about 19 with the truck running. I’ve changed the solenoid and check valve. Kinda stumped why the iwe is acting up with vacume? When you put vacume on the hubs the cvs quit turning and when you take it off they turn. Pretty stumped here. Anyone had this issue before? Service advance trac has flashed on a couple times in the past few months

 

The IWEs aren't fully engaged when they are grinding. You can then get burrs on the hub or IWE ends that make the semi-engagement permanent until fixed. The IWE wasn't fully disengaging from the hub when you put it into 2X.

 

Thank you for the reply. Wonder what is causing these issues since vacume is good?

 

I see there is a tsb for reprogramming the transfer case control module for this year truck due to iwe clicking etc. Does the ford dealership have to reprogram this or would somebody with for scan be able to? Thanks

 

I had similar problems and it turned out being a torn IWE membrane. I had recently had the ball joints replaced at Belle tire and they got too rough and damaged both of them. I ended up repairing the problem. Never going back there for anything. Of course they denied everything as usual. Not a hard job. May want to pull it apart and inspect them.

 

I'd start with the most notorious cause, the check valve. p/n YG-360 on Amazon, (or oem part for a bit more) located close to brake booster. My 2020 Lariat has gone through two, exact symptoms as you describe. Good luck. Always when temps cool down, on acceleration, speeds on hwy.

 

Thank you gentlemen for the replies. I did replace the check valve and solenoid but no change. Winter is here and this truck is useless without proper 4wd

 

I had the whole IWE system on my 2018 replaced under the extended warranty 2 years ago and has been working fine since. Main problem was with vacuum actuators sticking. Moisture freezing and corrosion I think were the cause. MN winters are the root cause of a poor design failing. Should have a simple push/pull cable setup.

 

if you unplug solenoid does it still make sound? You can simply let hubs stay engaged and use 4x4 as needed. There is a simple bypass, he hits how Ford likely would fixit.

 

OK, it's a 2018 F150, I know what those are, but don't know what trim package you have. It does make a difference between lower than and including an XLT, or higher trim package.
Too, you either have vacuum, or pressure? God doesn't like having both in the same space.
Does it sound like this?