Clunk in front end when engaging 4WD

Hey I have a nasty klunk in what seams to be my front end when I engage 4WD High. I have searched this forum and find plenty of info about the slip yoke, a rattle having to do with front shock perch torque, etc.

I am pretty sure my problem is something different.

The clunk is a very loud make you cringe noise when under any kind of load after engaging 4WD. I can feel the truck shutter as if one (Left Front) wheel becomes disengaged and then reengaged. This might happen once or several times in a few minutes and always goes away then the truck performs perfect in 4WD. I can switch to 4WD on level pavement and drive a mile or so and avoid this but if I have a need to accelerate between 5-30 seconds of shifting into 4WD I get one or more Clunks!

The dealer has replaced the IWE and is telling me they can't figure it out.

Anybody else had this problem and do you know the cause?

I had my transmission and transfer case rebuilt and before it wouldn't do this but now I know your pain with the clunk. Only is an issue when under any stress switching to 4x4 for the first few seconds.

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Hey Mike175 thanks for the reply but I don't see how my klunk could be a vacuum issue unless somehow vacuum is momentarily being applied.

Your thread describes a insufficient vacuum resulting in incomplete "dis" engagement of the hub lock and a grinding noise.

Maybe the word clunk is the wrong term. If you were in the truck when it happen you would likely say "Holy @#$% what the #$%! just happened?

Anyone else have a similar issue?

Old thread but exactly the same problem with my 2014...

Relentless said:

Old thread but exactly the same problem with my 2014...

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Hey Relentless, Did you figure out what the problem was? I had mine into the dealer, they replaced both hubs and axles but it still has the problem. The woodpeckers told me it is normal to do this but they would turn it over to the "ford tech guy" then they stopped returning my calls.

jasowiii said:

Hey Relentless, Did you figure out what the problem was? I had mine into the dealer, they replaced both hubs and axles but it still has the problem. The woodpeckers told me it is normal to do this but they would turn it over to the "ford tech guy" then they stopped returning my calls.

Click to expand...

Nope, dont know the cause. I've got 87k miles and mine just started doing this. I will live with it until something breaks.

To me, it doesnt sound like its in the front end. I think it's in the transfer case but dont know for sure yet.

I had the same problem. 4WD would be OK under light throttle but would clunk like crazy on anything other than light throttle.

In my case it turned out to be the IWE but my vacuum lines were brittle so I had them replaced with the Forged Offroad Silicon lines.



Between the two 4WD is now working great. Twice out to the dunes with 4WD and no clunk plus a really bad dirt hill where I was at 4K RPM with all four wheels spinning under full power and not a single clunk!

2010 – 2014 Ford Raptor Silicone IWE Replacement Forged Offroad

The factory IWE lines are crap and crack crumble apart after a few years. Get the IWE eliminator kit from RCV and never worry about any of that stuff again.