2021 Bronco Sport: Loud clunking noise on left side beneath car

BroncoBuster2

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It sounds like a broken drive shaft/CV linkage hitting the bottom while driving. The first time I took it to the dealer (August 2024), I was told it was a bad strut. It took three weeks to get my vehicle back due to difficulty getting parts. That ain't happening again. After replacing left side strut, the dealer called and said the right side strut was bad also, but part was readily available. So less than a year later, I have the same problem on the left side. I pulled the tire this morning and jacked up the lower control arm to see if I could find any play in the strut. It seemed all tight and not broken. Unsure?? However, when I pull out and push in on the drive shaft, there is some movement in and out. Maybe a 1/8". I don't know if that is an acceptable amount of play/clearance or not.
Question: Am I on the right track or am I overlooking something here?
This is my first ever post, so please let me know if I have left out any necessary details.
Thanks
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thomasm23

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It sounds like a broken drive shaft/CV linkage hitting the bottom while driving. The first time I took it to the dealer (August 2024), I was told it was a bad strut. It took three weeks to get my vehicle back due to difficulty getting parts. That ain't happening again. After replacing left side strut, the dealer called and said the right side strut was bad also, but part was readily available. So less than a year later, I have the same problem on the left side. I pulled the tire this morning and jacked up the lower control arm to see if I could find any play in the strut. It seemed all tight and not broken. Unsure?? However, when I pull out and push in on the drive shaft, there is some movement in and out. Maybe a 1/8". I don't know if that is an acceptable amount of play/clearance or not.
Question: Am I on the right track or am I overlooking something here?
This is my first ever post, so please let me know if I have left out any necessary details.
Thanks
How many miles are on your vehicle?

Which trim level do you have?

Do you go off road?

Please describe what you are doing when this sound occurs.
 

R W NORRIS New Mexico

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A driveshaft needs to have play to compensate for the movement of the engine and or the frame along with other items that do flex. I will say it should be OK with 1/8" or so, meaning I don't think that is your noise. Your noise, does it happen while driving or when you start out? Did you check your rotors and pads when you "jacked it up"? If it is a constant noise while driving at speed, what speed does it start or does it matter? Do you have a 1.5 L engine? If you don't trust the dealer, go to an independent garage and see if they will give a "free estimate" for repair. Ask them to ride along for a test. What you describe is not enough info for more suggestions, however let us know if it happens while turning or what speed and I am sure someone will try to help. Rodger
 

Leeford

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Its the RDU. Its not the strut or the CV. its the RDU. Its a common problem from the factory.
My 21 OB as started to make a noise on a right hand low speed turn. 49000 KM. Crap. Into the dealer it goes. Tey said without a blink, "RDU". What is the service bulletin?
 


Dude

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Leeford

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Dude

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Thanks! So the fix is a hose and some sealant...what's the chatter/shuddering from? Is it causing any other damage, ie wering down a part.
No the RDU vent hose and drain/fill the RDU is the beginning of a fix.

If the RDU issue gets worse or if the electric motor (2 in Badlands) or another failed component in the RDU Assembly is bad then that involves repair and replacement.

See the links to owners reports of what needed to be done to correct their RDU issue

And could it happen again to the same vehicle after it is fixed? I would guess it can.
 
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Cursed Bronco

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My 21 OB as started to make a noise on a right hand low speed turn. 49000 KM. Crap. Into the dealer it goes. Tey said without a blink, "RDU". What is the service bulletin?
Ford Bronco Sport 2021 Bronco Sport: Loud clunking noise on left side beneath car 1752500189556-8o

Be aware that this procedure often doesn't work. This is what I have seen from numerous posts here and on facebook, as well as my personal experience. It is usually too little, too late and requires the replacement of the RDU. In my case, I also had to replace an axle. The above TSB actually made my situation worse, and my inner tire would lock up under low speed turning maneuvers.
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