Drive Shaft Imbalances - What are they and what are the symptoms?

[John94]

So I have been lurking around the issues section of this forum relentlessly for some time now, looking for anything that seems similar to the issue(s) I have been having with my Bronco, and I believe I am beginning to find a theme.

My Issue

I have been experiencing SLIGHT vibrations at highway speeds in my steering wheel, seat and floorboards for sometime now. Noticed at approx 8k miles.
Having a dealer diagnose this has been a huge issue as the vibrations are indeed mild, so much so that when you feel it in the steering wheel, if you were to take your hands off and stare at the wheel, you would see NO visible shake.

The vibrations are intermittent, they seem to occur approx 75% of the time. When present they are cyclical (sinusoidal).. 3-5 seconds vibration, 3-5 seconds perfectly smooth as god intended.

Wheels & Tires

Everyone is very quick to point to a tire/wheel balance issue - which is logical as that is often the culprit. Or folks remind me that off-road tires have aggressive tred patterns that could led to this vibration behavior.

1. I have had my tires hunter road force balanced three times. No resolve
2. I have had my tires rotated. no resolve
3. I have OEM everything
4. My Buddy has an identical SAS bronco. We went so far as to swap wheel/tires entirely. My vehicle still vibrated, his did not.

Thus, we can safely rule out tires and wheels

Other folks issues

I am beginning to see other people with stock bronco's complaining about cyclical vibrations on the highway or cyclical droning sounds on the highway and so on.

thus I began to research deeper and found that the last gen Ford Ranger had Driveshaft balance issues that were causing highway vibrations, this was acknowledged by ford and fixed via a few different methods.

So that led me to Driveshafts

Drive Shafts

Ford already has an official recall for the Front Drive Shaft due to a failing boot, so the idea that the rear drive shaft (or front) has other issues isn't far fetched.
From what I understand if your drive shaft(s) get even slightly out of balance, it can cause vibrations - similar to what I am describing on the highway.
Balance issues can happen from a number a reasons, debris getting lodged in the shaft, intense off roading and perhaps straight up poor factory assembly.

Admittedly I have taken the bronco off road multiple times, grabbed a few inches of air on the sand dunes, smashed it through mud and rocks...etc
so perhaps I caused balance issues?



Anyone with drive shaft knowledge

Do these symptoms sound drive shaft related to you?
is anyone else experiencing odd vibrations?

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[Bmadda]

Driveshaft issues, whether they are caused by balance, bad u-joint/cv, or bent shaft etc, are always "torque sensitive". Get on a smooth road at a steady speed above say 45 mph and tip in and out of the throttle. If the vibe intensifies under accel, and is much less noticeable, or even completely gone on decel, then it's likely driveline/driveshaft related. Note that the front driveshaft will not be a factor in 2wd, but in 4wd (on a straight smooth road where you know you can lock it in at some speed) it will. Other things that cause vibrations IE wheel balance etc, will not be changed by applying and releasing torque this way.

EDIT: It is also possible on a Bronco to drive in 2HI at highway speeds w/the front driveshaft removed. I have had to do this to isolate highway vibrations on Jeeps in the past

 

[dgorsett]

You could also drive in 4H with the rear removed

 

[Blmelite]

I unfortunately have the same issue it’s been to the dealer twice. With no solution it’s about to go back for a third time now concerning the same issue. However, now I am getting a clunk at takeoff and stop. On occasion.

 

[John94]

I unfortunately have the same issue it’s been to the dealer twice. With no solution it’s about to go back for a third time now concerning the same issue. However, now I am getting a clunk at takeoff and stop. On occasion.

Same! I noticed the clunk last week.
Please let me know what happens when you bring it back for the third time... after that you can lemon law it!

I can't for the life of me get dealers to acknowledge the issue... as is the trouble with intermittent issues.

please keep me posted!

 

[John94]

any updates?

 

[Brnzbronc]

I’m having the same issue , I believe it’s the slip joint on the driveshaft. Same issue with the f150’s with 1 piece drive shaft. The fix for the f159 was to remove the drive shaft and add more grease. I can tell there is some movement in that joint.

 

[Trooper19]

I do work at drive line shop , we have seen many vehicles with similar problems. The Bronco shafts are built with High-speed cv's
The symptoms do sound like A shaft imbalance . I hope your local dealer can work with you to help smooth things out.
We are work with our local dealers for their customers.
If you need to look for a shop to do drive line work call around, there are shops like mine that specializes just in drive shaft repairs.
Hopefully you find one that has experience with the high speed cv's.

 

[flip]

Dealer needs to put an electronic vibration analyzer (VCMM) on it and find out what the frequency, order and magnitude of the shake. This way they can find out if it's driveshaft, engine, accessory rotational speed then go into it. Depending on the speed, don't rule out some sort of weird torque convert clutch lockup problem. They can rule this in/out buy manipulating the TCC function with FDRS while driving. Can the problem be recreated on a lift?

Driveshaft typically is a drone/boom between 45-75. What was the the road force and runout readings on all of the wheels/tires?

 

[ferbm]

I just noticed this or a similar vibration while towing my fishing boat (3000lbs). It was only noticeable above 65mph. 2002 Badlands Sas 4-door. Not sure if that helps to isolate the issue, but I do not notice it when trailering lighter stuff (SXS) or without the trailer. It wasn't awful, but very noticeable.

 

[Blakshukvw]

I’m having a slight vibration on my 23 2.7T Wildtrack.
What I experience is a growl and vibration in the floorboard anytime it’s in 4A or 4hi. This occurs at highway speeds usually. Something above 55. It Usually is detectable under load while going uphill, obviously a a situation where the front axle is doing its share of pulling. I can also induce the noise with judicious throttle application. This growl never occurs in 2hi. Im certain it’s in the front driveshaft. My dealer service center claimed today they couldn’t replicate it. So I went up there and took the service writer for a drive. I made it do it and he claimed he didn’t hear it. He asked me to bring it back when conditions were dry so he could attempt to observe it again. Even though he never heard the noise, he was already telling me it’s normal for 4wd to make noises while turning and other situations, which isn’t at all what I described. So the guy who claimed to not hear my noise already knows the problem. SMH.

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