GEN 2 Name that noise (2017)

My 2020 did this on the way home from the dealer the day I purchased it. Throttle sensitive . Dealer replaced the check valve and said the 4x4 switch was also intermittently causing it to engage the iwe's. They had to order the switch. Tech said he took switch apart and cleaned it for now. Was good for a week, started all over again. 4A it goes away. How often do these check valves fail? I'm kinda doubting the switch diagnosis. Guess I'll run in 4A till they replace the switch. Don't wanna ruin the iwe's, etc.

fordfreek said:

My 2020 did this on the way home from the dealer the day I purchased it. Throttle sensitive . Dealer replaced the check valve and said the 4x4 switch was also intermittently causing it to engage the iwe's. They had to order the switch. Tech said he took switch apart and cleaned it for now. Was good for a week, started all over again. 4A it goes away. How often do these check valves fail? I'm kinda doubting the switch diagnosis. Guess I'll run in 4A till they replace the switch. Don't wanna ruin the iwe's, etc.

Click to expand...

It’s highly unlikely that 4WD switch is root cause; if that were the case, you’d see “4x4 shift in progress” messages and the system would be changing state back and forth.

I don’t understand why these dealers have such a hard time diagnosing a simple vacuum operated system. The Workshop Manual even has a revised pinpoint test that allows for an easy diagnosis.

I would request that they stop guessing on the issue and perform the pinpoint test to get it resolved. Throwing parts at it will only cause repeat repairs attempts and waste your time going back to the dealer

Well, it took him 2 1/2 hours to arrive at this diagnosis as well. I figured he threw the switch in as a second problem for flat rate reasons and the real fix was the vacuum check valve. It seems like it's very intermittent. Did it once yesterday about a mile after a restart, then never did it again in the 24 mile trip. This morning it took about 30 miles to do it from a cold start. Did it 2 more times after that, then I just put it in 4A and it was gone after that. The system holds vacuum from the check valve out to the iwe's, and I swapped a brand new solenoid in myself with no change.

legitky said:

Mine is definitely not blue, so going to order the part and swap them out. Assuming that gets rid of the noise, do you think there's any resulting damage that I should also get checked out? I'm hoping this would fall under the powertrain warranty if so

Click to expand...

The blue one is the updated part.

@FordTechOne I've been researching this since you brought it up the other day, seems like most people with grinding IWEs is at low speeds or when turning left - my noise has just been at highway speeds under turbo. Should I be worried about any other damage to hubs or bearings or anything, or just the vacuum problem?

Plan on getting to the dealership first thing Monday morning to swap it out

legitky said:

@FordTechOne I've been researching this since you brought it up the other day, seems like most people with grinding IWEs is at low speeds or when turning left - my noise has just been at highway speeds under turbo. Should I be worried about any other damage to hubs or bearings or anything, or just the vacuum problem?

Plan on getting to the dealership first thing Monday morning to swap it out

Click to expand...

The IWEs and hubs aren't typically damaged by slight/intermittent partial engagement from a momentary loss of vacuum. It would take prolonged IWE to hub drag to damage the teeth to the point that it would make noise during normal engagement or fail to engage. Let us know how the appointment goes.

Brought my truck in to the dealer to have my 4wd switch installed today. After they installed the switch they must have realized that wasn't the problem. They had the truck for about an hour and a half. Turns out it was a bad check valve. I had tee'd in a vacuum gage in the supply side of the system at the solenoid so I could monitor what was going on. It would start to lose vacuum at light cruise throttle position. When it got too low I would just let off the gas and bring it up to normal. This allowed me to run 2wd and keep it from grinding. FYI, it had the updated valve in it already. I wonder if they used my gage to help diagnose the problem. I left it all hooked up .

My truck is having a similar issue, looking for advice. I recently went on a 30 minute highway drive and exiting the road (was a spirited drive including 100mph, and full throttle from 0mph to 85) and the truck started vibrating on deceleration when I exiting the highway. I pulled over immediately and checked for visual damage, nothing. Then the truck drove normal as I limped home. Now it has a groan, vibration under acceleration. Parked at my shop ready to fix it. Any input is greatly appreciated. Thanks again I followed FordTechOne info about putting it into 4A and it maintained the growling noise, it is not that load, just feel like something is going to break.