Rotational thumping or clunking noise

[NickW]

I’ve read a lot of threads about clunking and thumping noises, but I can’t find one that specific to my issue and that has a solution.

Without any incident or recent work done on the truck, I have a thumping/clunking noise coming from the truck. Pretty loud and sounds like it’s in the front end or maybe a driveshaft. It’s a rotational sound so the faster I go, the faster the frequency of the noise. Does this sound familiar for any common issues? There was a thread in the gen 1 section that mentioned the transfer case yoke, so I’m wondering if that could be it.

Thanks for any input

 

[NickW]

An update to this issue for anyone having a similar problem in the future, I was able to make some progress on the source of my issue. While driving in 2H the "thumping" noise is quite noticeable, when I go to 4H the noise stops. So it looks like yet another problem with the **** IWE. I had both front hubs and IWEs replaced about 28k miles ago by the dealer under warranty. Unfortunately, I'm no longer under warranty and the parts/labor for that job is no longer under warranty either, so I will be doing this one myself.

@FordTechOne I've seen in a few threads where you mention the importance of following the install procedure on this job and it sounds quite specific. Would it be possible for you to share that full procedure? I'd like to make sure I do this correctly. Thanks very much!

 

[Nex]

How's the check valve look?

 

[NickW]

Good, as far as I can tell. The connections all appear good and the valve itself is only allowing air flow one-way. It was replaced with new when the hubs and IWEs were replaced almost 2 years ago.

 

[FordTechOne]

You’ll want to verify that the system holds vacuum before moving forward with part replacement. As far as the IWEs, they need to be compressed with a vacuum pump before installation into the wheel knuckle. The depth of the axle shaft needs to be verified as well, the minimum measurement is 15.5mm.

 

[Old-Raptor-guy]

every IWE I have seen and I have seen a bunch made a ratcheting or grinding type noise, why because that is what is happening. The teeth on the IWE are grinding on the teeth on the axle. Thumping noise seems like it would be something else, but if you can prove me wrong please do so (post your results please, so we can all learn)

 

[NickW]

You’ll want to verify that the system holds vacuum before moving forward with part replacement. As far as the IWEs, they need to be compressed with a vacuum pump before installation into the wheel knuckle. The depth of the axle shaft needs to be verified as well, the minimum measurement is 15.5mm.

View attachment 429390

Thanks for this. I checked the vacuum on the system. 15 inches at the line going to the IWE in 2WD (on both sides). Checked vacuum at the line that feeds the IWE system before it hits the check valve and it read 15 inches as well.

Solenoid also appears to be working every time I checked by going from 2WD to 4WD. It "clicks" and the vacuum drops/comes back as it should.

I also raised the front end so that the wheels were off of the ground and applied 15 inches directly to each IWE. The wheel spines independently from the half-shaft. Release the vacuum and the half-shaft spins with the wheel. Everything appears to work as it should from what I can tell.

I connected the system back together and started the truck with the front wheels off the ground. Same results. In 2WD the wheel spins independent of the half-shaft. In 4WD the half shaft spins with the wheel. I lowered the front end, take it for another test drive. No change. Fairly loud rotational "thumping" noise that seems to come from the front left as soon as I start driving. The thumping can also be felt in my feet.

Traveling on a straight road so as not to turn the wheels and I engage 4WD...the thumping noise cuts out completely. Switch back to 2WD and the thumping returns.

I'm not 100% that the IWE and/or the hub assembly are bad, but seems to be the most likely problem to me, based on what is happening. I even went as far as to run all new vacuum tubing from the solenoid to both IWEs as a test, to make sure there's not a crack or an intermittent leak in the existing tubing. No change. Originally I was thinking a CV joint was bad, but the thumping goes away every time I go to 4WD and comes back once I go back to 2WD.

I'm at the point now of pulling the hub assembly apart and visually inspecting the wheel bearing and IWE to see if there is visual damage, unless you or anyone else has any other ideas on what I can/should check?

Thanks again for the input.

 

[NickW]

Update: Found both front CV axles to be bad. Well, needing rebuilding and repacked. Strange to have both go bad at the same time. One was much worse than the other, but both were bad. Seems obvious now, but I’ve not ever had CV axles present these symptoms when going bad. Hopefully this can save someone else some diagnostic time!

 

[timothy]

Update: Found both front CV axles to be bad. Well, needing rebuilding and repacked. Strange to have both go bad at the same time. One was much worse than the other, but both were bad. Seems obvious now, but I’ve not ever had CV axles present these symptoms when going bad. Hopefully this can save someone else some diagnostic time!

Finally I found someone having almost the exact same issues as me with my non-Raptor F-150 Fx4, I registered just ask you some questions. I initially thought it was the CVs as well but that doesn't make sense to me as the CVs should not be turning in two-wheel drive because the IWE's, and if you put in four-wheel drive then the CV should be working so where is that noise exactly coming from? Mine is thumping pretty bad I can feel it in my feet. I've already replaced the hub that I thought it was, flushed out the transmission and transfer case and check u-joints on the front and rear drive shaft. It doesn't make sense to me how the CVs can cause this into-wheel drive if they shouldn't be turning.

 

[timothy]

Finally I found someone having almost the exact same issues as me with my non-Raptor F-150 Fx4, I registered just ask you some questions. I initially thought it was the CVs as well but that doesn't make sense to me as the CVs should not be turning in two-wheel drive because the IWE's, and if you put in four-wheel drive then the CV should be working so where is that noise exactly coming from? Mine is thumping pretty bad I can feel it in my feet. I've already replaced the hub that I thought it was, flushed out the transmission and transfer case and check u-joints on the front and rear drive shaft. It doesn't make sense to me how the CVs can cause this into-wheel drive if they shouldn't be turning.

I'll answer my own question here for anyone researching or trying to figure out this problem on their own. Lariat trims and up have a different style transfer case that runs the front drivetrain all the time, minus the hubs, including the raptors transfer case that have a little different design from all.