I have a 2017 f150 3.5l ecoboost 4x4. There is an intermittent grinding noise coming from my front wheels. It happens mostly when I accelerate, trying to hold a steady speed. I know this is a common problem with Fords. I used a hand vacuum pump and hooked it up so I can see when it loses vacuum while I drive. At about 3.5 inches, the grinding noise happens. When I let off of the accelerator the vacuum catches back up again.

With the hand vacuum pump I checked the vacuum line going to the wheels, the vacuum supply line, the new check Valve assembly, and the reservoir.

I have replaced the check valve assembly, the IWE solenoid, both of the 4wd actuators, and even both hub assemblies.

I know if I take in to the dealer, they are just going to give it back to me if they can’t replicate the seemingly random sound.

I am completely lost at this point. And ideas for possible solutions would be amazing.

 

You should have 15 inches going to the IWE when in 2wd mode. The entire purpose of the vacuum resevoir tank and check valve is to hold that much vacuum when accellerating and the engine manifold is not putting out enough vacuum.

 

Thank you. That’s why I started there. It doesn’t happen necessarily when I ale off from a stop light or something. It seems to happen when I am trying to maintain a steady speed. Like everything is fine and then there is a sharp drop and when I let off of the accelerator, it stops. When it starts I let off the gas and it will stop, and then I will press the gas again and it catches back up. Sometimes it doesn’t catch up and I have to let off a he gas and back on several times.

 

Sounds like the classic checkvalve trouble. New ones have been known to be bad as well. I suggest you try a YG360 valve, can be gotten at any parts store. If that doesn't solve the problem, TSB 20-2013, might help you out.
Not trying to insult you, but you did put it in with the proper orientation?
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No worries about the possibility insulting me. lol. I’m learning as I go.

I appreciate the suggestion. I’ll go buy another check valve, it can’t hurt. What’s another $8 when I’m already $650 deep chasing the problem. Also, I never changed the orientation of the assembly that I purchased and I have hooked the vacuum pump up to it and it holds but that is with no jostling around from driving.

 

Hi chainzaw. Were you able to fix your issue? The way you described your noise sounded like my problem. The dealership shop Supervisor knew exactly what was happening. He said the front wheel hubs were trying to engage. He simply disconnected the check valve and plugged it up. This was the three years ago.