Thumping Noise in 4WD

[rtd16]

Hello all, I have a 2022 Big Bend, with the Eibach Pro Truck Lift coilovers at all four corners with Zone UCAs. Today was really the first day I exercised it in 4WD with snow in upstate NY. Whenever it is in 4WD, there is a repetitive thumping noise coming from the front driver's side area. It's almost like the sound when you have a rock stuck in the tire tread, but a little more amplified. Tire pressures are all normal, and only happens when I am in 4WD (I only had it in 4Hi not 4Lo). I can definitely hear/feel it taking off from stops but once I'm up at 50 or so I can't really notice it with the wind/road noise. Anyone have anything similar or any thoughts? Thanks

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[PWillette]

Hello all, I have a 2022 Big Bend, with the Eibach Pro Truck Lift coilovers at all four corners with Zone UCAs. Today was really the first day I exercised it in 4WD with snow in upstate NY. Whenever it is in 4WD, there is a repetitive thumping noise coming from the front driver's side area. It's almost like the sound when you have a rock stuck in the tire tread, but a little more amplified. Tire pressures are all normal, and only happens when I am in 4WD (I only had it in 4Hi not 4Lo). I can definitely hear/feel it taking off from stops but once I'm up at 50 or so I can't really notice it with the wind/road noise. Anyone have anything similar or any thoughts? Thanks

Could possibly be a CV joint. How much is it lifted?

 

[rtd16]

About 3"

 

[Baseaf]

First time 4x4 has been used since you lifted it?

 

[rtd16]

Yes

 

[uncledoodoo]

are you off-road in snow or on-road? On-road you should be using 4A, not 4H. If you don't have 4A, then maybe the snow isn't slipping at all and your transfer case is hopping like it would on dry pavement?

 

[kodiakisland]

50mph in 4WD on the highway or dirt roads?
Most likely a CV joint.

 

[rtd16]

are you off-road in snow or on-road? On-road you should be using 4A, not 4H. If you don't have 4A, then maybe the snow isn't slipping at all and your transfer case is hopping like it would on dry pavement?

50mph in 4WD on the highway or dirt roads?
Most likely a CV joint.

Thank you uncledoodoo and kodiakisland. Yes it was on road (pulling out from a gravel road to 'normal' paved road and accelerated up to about 50. Slowed back down for a stop light, and when I pulled away is when I heard the clunking or thumping noise. Put it back in 2H, no noise, back in 4H noise is back (repeated several times) and it's only from the front left. Uncledoodoo I understand what you are saying about the 4H on dry pavement and the wheel hop effect, but this doesn't 'feel' like that if that makes sense.

 

[Baseaf]

Yes

Install error possibly? Either way it sounds like a bad axle. A small lift like that doesn't cause them to fail like that. I wheel mine on 33s hard with a spacer lift and have had no issues.

 

[kodiakisland]

Install error possibly? Either way it sounds like a bad axle. A small lift like that doesn't cause them to fail like that. I wheel mine on 33s hard with a spacer lift and have had no issues.

That would be my first guess without looking for obvious signs on the side the noise is coming from. A lot of broncos have had CV damage after lifts if the installer allowed the axle to hang freely or just didn’t pay attention.

 

[rtd16]

That would be my first guess without looking for obvious signs on the side the noise is coming from. A lot of broncos have had CV damage after lifts if the installer allowed the axle to hang freely or just didn’t pay attention.

That's interesting and still seems like a design issue to me. I watched separate videos of the axle shafts being removed, and in both it seemed to me they needed to apply some significant force to get the splined shaft out of the differential carrier. It wasn't as though it just slipped right out, which tells me by dissembling that area only to the point of fitting the new coil over in shouldn't allow the shaft to slide that far out of position...

 

[rtd16]

Update if anyone is still monitoring this one. I took it to the dealer. They said they also heard the noise when turning in 2WD which would point to a CV joint, but I haven't been able to replicate that. They stated it's most likely the CV joint making the noise from being over extended from the lift kit installed, and there isn't anything they can do. I believe the lift is only at about 3" (it's the adjustable Eibach Pro Truck Lift). I measured the axle shafts with an inclinometer. Driver's side was about 17 degrees and passenger 11 degrees. The service manual states to ensure the inner CV is not bent more than 18 degrees. So technically it should be fine. Don't people out there lift these as high as 6"? I don't see how 3" is going to over extend the axle shaft. I'm also not sure if the differing angles is normal, since I didn't measure them before the lift. I suppose next step would be to either:
1) Pull the axle shaft to check if it isn't fully inserted as kodiakisland mentioned.
2) Since it's adjustable, lower the lift height down and see if the noise stops at less of an angle...

 

[GLittleBronquito]

Update?
I having the same problem.

 

[Silver-Bolt]

Update if anyone is still monitoring this one. I took it to the dealer. They said they also heard the noise when turning in 2WD which would point to a CV joint, but I haven't been able to replicate that. They stated it's most likely the CV joint making the noise from being over extended from the lift kit installed, and there isn't anything they can do. I believe the lift is only at about 3" (it's the adjustable Eibach Pro Truck Lift). I measured the axle shafts with an inclinometer. Driver's side was about 17 degrees and passenger 11 degrees. The service manual states to ensure the inner CV is not bent more than 18 degrees. So technically it should be fine. Don't people out there lift these as high as 6"? I don't see how 3" is going to over extend the axle shaft. I'm also not sure if the differing angles is normal, since I didn't measure them before the lift. I suppose next step would be to either:
1) Pull the axle shaft to check if it isn't fully inserted as kodiakisland mentioned.
2) Since it's adjustable, lower the lift height down and see if the noise stops at less of an angle...

You are at 17 degrees with the vehicle weight loading the suspension. What is your measurement at full droop? You have a CV issue. Either it is not fully seated back into the diff or it is binding. Driving it is making it worse and more expensive to repair. Look into a diff drop to get your CV's at a more reasonable angle.

 

[rtd16]

Thanks Silver-Bolt. Since that post I had the axle changed out, and the problem persisted. I believe this is more of an issue with the differential than with the axle itself. Ford apparently opened a "case" about six months ago on it, but I've never heard anything from them. Dealer would only work on it if I paid since the lift voided the warranty, and I dont have the cash for that. I ultimately traded it in. The payments were too much for a suspect four wheel drive system.

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