Front end clunk in 4hi

[Bret56]

So I’m getting a loud clunk out of my front end, this only happens in 4hi and not 4auto or 2wd. Haven’t tried 4lo.

Before this turns into a pissing match about how to use 4wheel drive please read and understand this is for diagnosis purposes only.
The initial problem presented OFF ROAD, in slippers wet/mud conditions on a gravel/dirt Forrest service road in bad shape, 4hi was warranted and needed. This is when I heard the clunks. It Was not dry, it was not on pavement, I’ve been driving trucks and 4wheel drives for 25 years, and was also a mechanic before my current job.

My truck, 2022 f150 lariat 2.7 with 4auto, levelled 2” on 285/75/17 tires.

My F150, in four high when I turn either left or right makes a loud clunk noise like something shifting then I straighten out give it some gas and clunks as in something settles back into place. Only clunks once during a turn then not again, once I straighten out and give it some decent throttle it clunks again as if something is settling back into place or moving. Then it will make the clunk again in another turn.

I drove my friends truck, 22 f150 xlt, only difference in drivetrain is his does not have the 4 auto. Same exact same test loop, his does not make the clunk at all. Not once. Exact same level and tire diameter. U can feel the 4wheel drive start to push back and no clunk, where mine clunks hard.

I crawled underneath it doesn’t seem like anything shifting like my lower control arm, cam bolts or my struts or anything like that, it gets to the point when you turn you just start to feel the push of the four-wheel-drive and she goes clunk and then you straighten back out everything’s fine, give it some hard acceleration and it goes clunk again and then everything’s fine until another turn.

Any ideas? Anyone else had the same issue? I do not have IWE. Diff doesn’t make sense to me to have this noise clunk, could it be a bad hub engaging and diss engaging? Or a transfer case? I’ve tried to see if any of the mounts have marks from shifting/moving from a loose mount but nothing.

Thanks in advance for the help and read.

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[Desertdweller]

I had the exact same issue on my '21 KR. After reading the manual. I realized it is not advisable to run 4 Hi on dry roads. They acknowledge that it might result in a clunking noise.

 

[Bret56]

I had the exact same issue on my '21 KR. After reading the manual. I realized it is not advisable to run 4 Hi on dry roads. They acknowledge that it might result in a clunking noise.

Clearly an issue if u drive in 4hi on dry pavement.
I don’t know why everyone on this site thinks that every single person has no idea how to use 4wd.
This issue happens off road, on gravel, on dirt, in mud. Only in 4hi and 4lo. Not 4auto.

took it to the dealer and test drove many others. They all do it. It’s the electronic 4auto transfer cases that are the problem, the raptor and 402a tremor that get the hilock transfer case that engage manually when in 4hi and 4lo but electronic magents in 4a. The lariats, platinum and king ranch do not have the manual locking on any of that.
Major design flaw on fords part. But at least I found out they all do it.

 

[Xman]

Bret, very interesting information. I had this exact situation happen to me in 4H when I first got my 2024 Lariat last October. The clunks were very loud and happened in several slow speed situations while in 4H that day. It hasn't occurred since, but I have been trying to understand why they occurred. I am new to 4WD and how Ford's system works. This is very helpful.

Am I correct in assuming that this loud clunking does not occur in XLTs with 4WD?

 

[Bret56]

Bret, very interesting information. I had this exact situation happen to me in 4H when I first got my 2024 Lariat last October. The clunks were very loud and happened in several slow speed situations while in 4H that day. It hasn't occurred since, but I have been trying to understand why they occurred. I am new to 4WD and how Ford's system works. This is very helpful.

Am I correct in assuming that this loud clunking does not occur in XLTs with 4WD?

You are correct that a xlt would not do it, it does not have the 4a function. It’s only 2wd and 4wd, no magnetic clutches to operate 4a so its a full manual locking transfer case.

the issue that happens, in a regular 4wd transfer case when your in 4hi or 4lo and u turn and start to feel the bind the wheels “hop” and u feel that, but in a manual locking tcase it pushes thru and keep going. In the magnetic clutch tcase like every model with 4a (minus the raptor and tremor high package) when in 4hi and 4lo u have magnetic clutches holding it in 4wd and when it reaches the binding point like u feel in a manual locking tcase the clutches aren’t strong enough and they let go or slip then catch again. Thats the clunk/bang u feel and hear. This shouldn’t happen but it does for some reason. Not sure if the clutches aren’t strong enough or if its just a lack of high enough voltage to the clutches creating a weaker strength than what’s needed.

not the end of the worlds but when ur actually off road and it happens when turning in 4hi it gets annoying

I specifically wanted a 2.7 engine, but in hindsite if I knew this was gonna be a thing I would have opted for the tremor high.

 

[Xman]

Should I just use 4A when I'm off-road instead of 4H with my Lariat? What is the advantage of 4H over 4A?

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