[Samsam]

had a check valve replaced three weeks ago, after low rpm grinding from front end. After check valve, noise was still there. So, went back and dealership rebuilt front diff and changed driver & passenger IWEs. Fast forward today, grinding noise isn’t as prominent but while turning left - it’s there. Grinding noise under 1500 rpm and under 60km/h.

anyone have any ideas?

 

[snakebitten]

I still think you are losing vacuum and the IWE is partially engaging. Does the grinding dissappear in 4WD?

 

[Samsam]

I still think you are losing vacuum and the IWE is partially engaging. Does the grinding dissappear in 4WD?

that’s correct, it goes away in 4wd. Could it be that there is a leak in the hose going from the IWE up to the valve? Right side is smooth as butter, just the left.

 

[snakebitten]

There's more than one possibility of not having sufficient vacuum to keep that (or both) IWE from trying to engage. The most common is that check valve. But yea, I'm sure with that convoluted vacuum line loop Ford has that there's multiple places that it could leak.

The worst thing about what you describe is that you have new IWE's and they will be damaged again in short order if the grinding is still there. I'd drive in 4A until you can find the cause for weak vacuum.

Or you could simply remove vacuum altogether and just allow the IWE's to stay engaged. It doesn't harm anything other than a little hit on fuel economy because you are turning the front axles even in 2WD. It's actually less of a fuel hit than 4A when you think about it.

 

[Samsam]

There's more than one possibility of not having sufficient vacuum to keep that (or both) IWE from trying to engage. The most common is that check valve. But yea, I'm sure with that convoluted vacuum line loop Ford has that there's multiple places that it could leak.

The worst thing about what you describe is that you have new IWE's and they will be damaged again in short order if the grinding is still there. I'd drive in 4A until you can find the cause for weak vacuum.

Or you could simply remove vacuum altogether and just allow the IWE's to stay engaged. It doesn't harm anything other than a little hit on fuel economy because you are turning the front axles even in 2WD. It's actually less of a fuel hit than 4A when you think about it.

That’s right, I am worried about damaging these IWEs, since they’re..a day old haha. I will drive in 4A for the weekend and hopefully they’re able to find the leak on Monday. Will being in 4A damage anything, especially at highway speeds?

Would it be bearings if the noise develops while in 2WD?

 

[Arkansas Eco]

You can drive in 4A 100% of the time whether the road is dry or wet or whatever without harm to anything.

 

[Justinjs]

That’s right, I am worried about damaging these IWEs, since they’re..a day old haha. I will drive in 4A for the weekend and hopefully they’re able to find the leak on Monday. Will being in 4A damage anything, especially at highway speeds?

Would it be bearings if the noise develops while in 2WD?

Is it warranty work or are you having them fish for a fix?

 

[Samsam]

Is it warranty work or are you having them fish for a fix?

It’s all warranty work. Just frustrating as the check valve is relatively new, IWE actuators are new and rebuilt front diff.

 

[Samsam]

You can drive in 4A 100% of the time whether the road is dry or wet or whatever without harm to anything.

Does the 4A have the same affect on the IWEs as 4H?

 

[Justinjs]

Does the 4A have the same affect on the IWEs as 4H?

My understanding is...yes. the front end is being pushed but the t case isn't engaged... true @snakebitten ?
For the life of me I can't wrap my head around 4a.

 

[Justinjs]

What year and how many miles?

It could be bad iwe, I had a few bad ones plus one broken one when I did mine. Also bad CV axle could be the culprit. It's strange they would keep replacing stuff that is easily tested.

 

[Samsam]

What year and how many miles?

It could be bad iwe, I had a few bad ones plus one broken one when I did mine. Also bad CV axle could be the culprit. It's strange they would keep replacing stuff that is easily tested.

2019 with 53000 kms. They found metal flakes etc in the front diff (rebuilt), inspected and replaced the IWEs as they had gone “bad” but wheel bearings were good. Foreman did say the check valve and solenoid were good to go and good vacuum. That’s why I’m stumped. Could the valves go that quickly? At this rate, I’ll have to buy in bulk haha.

 

[Justinjs]

The check valves are pretty simple, not sure how often they go bad.

I'm wondering if there is a leak in the line? But a specific rpm under a specific speed seems too perfect. Bad CV axle? Any way you could take a video of it?

 

[Samsam]

The check valves are pretty simple, not sure how often they go bad.

I'm wondering if there is a leak in the line? But a specific rpm under a specific speed seems too perfect. Bad CV axle? Any way you could take a video of it?

Absolutely, I’ll make one in the morning. It isn’t as loud as it was before the front diff rebuild and IWEs put in. But mostly notice is when turning left. Turning right is smooth as butter.

 

[snakebitten]

My understanding is...yes. the front end is being pushed but the t case isn't engaged... true @snakebitten ?
For the life of me I can't wrap my head around 4a.

4A 4Hi 4Lo are all exactly the same as far as IWE is concerned.
It's easier to get your head around if you ever had a truck with manual locking hubs. The IWE is nothing more than a hub that is locked/unlocked via vacuum, rather than you getting out of the truck and turning the lock yourself.

So it is very much a separate thing than transfer case settings. You could manually lock your hub in 2WD, but since the transfer case wasn't "transferring" torque to the front differential, you were still just driving the rear wheels, albeit you ARE turning the front axles since the hub is locked. (a small added rotational load)

IWE deletes are very similar to just leaving those old manual hubs locked full time. And exactly the same thing as just nixing Ford's vacuum to the IWE altogether.

4A is designed to be used on high traction conditions, so there's no risk driving in 4A. My Powerboost automatically engages 4A if you switch to Sport Mode. Think about that for a second.

I think Ford should include 4A on all 4x4 F150's.

 

[Samsam]

4A 4Hi 4Lo are all exactly the same as far as IWE is concerned.
It's easier to get your head around if you ever had a truck with manual locking hubs. The IWE is nothing more than a hub that is locked/unlocked via vacuum, rather than you getting out of the truck and turning the lock yourself.

So it is very much a separate thing than transfer case settings. You could manually lock your hub in 2WD, but since the transfer case wasn't "transferring" torque to the front differential, you were still just driving the rear wheels, albeit you ARE turning the front axles since the hub is locked. (a small added rotational load)

IWE deletes are very similar to just leaving those old manual hubs locked full time. And exactly the same thing as just nixing Ford's vacuum to the IWE altogether.

4A is designed to be used on high traction conditions, so there's no risk driving in 4A. My Powerboost automatically engages 4A if you switch to Sport Mode. Think about that for a second.

I think Ford should include 4A on all 4x4 F150's.

Ah that makes a lot more sense. Sorry for the ignorance, haha. I’ll run it in 4A until I can get in the dealership on Monday. Just hoping I don’t get turned away with a “oh..that’s normal” haha

 

[Justinjs]

Ah that makes a lot more sense. Sorry for the ignorance, haha. I’ll run it in 4A until I can get in the dealership on Monday. Just hoping I don’t get turned away with a “oh..that’s normal” haha

Definitely not normal, iwe issues have plagued me for about 3 months now, mostly my ignorance a d faulty aftermarket parts.

 

[snakebitten]

No reason to be sorry!
And although dealerships deserve that quip, it's NOT normal, but is all too common.

That check valve is a $6 piece of cheap plastic. You could have a poorly functioning new one. A fella here recently took his off and could blow through it both ways, which is not supposed to be possible. But by blowing through it the wrong way it clicked into place and became one-way again.

You can also install 2 of them back to back for redundancy. Less likely for 2 of them to fail simultaneously. They are easy to reach and verify that they are working properly.

 

[Samsam]

No reason to be sorry!
And although dealerships deserve that quip, it's NOT normal, but is all too common.

That check valve is a $6 piece of cheap plastic. You could have a poorly functioning new one. A fella here recently took his off and could blow through it both ways, which is not supposed to be possible. But by blowing through it the wrong way it clicked into place and became one-way again.

You can also install 2 of them back to back for redundancy. Less likely for 2 of them to fail simultaneously. They are easy to reach and verify that they are working properly.

Could there also be a leak in the actual line from actuator up to the valve? I’m going to buy a valve to keep on hand but also inspect the lines. I’m sure it is somewhat exposed, so prone to the elements. I’m in wonderful Canadia..figure the seasonly road offerings might have knicked something? Or the tech just didn’t connect it properly?

 

[snakebitten]

Of course there could be. There could be a leak in the vacuum reservoir. The whole IWE vacuum harness is a single assembly that Ford sells. Depending on the age of the truck, you might just replace the whole thing if you can't isolate it.