Rear end makes a grinding noise when driving slowly over bumps?

Tiny
PJW1977
  • MEMBER
  • 2001 GMC YUKON
  • 4.6L
  • V8
  • 2WD
  • AUTOMATIC
  • 283,000 MILES
When I drive over certain bumps always while driving slowly, the rear passenger side, at least that is where it sounds like it is coming from, has started making an unbelievable grinding noise for a second or two, I thought the whole rear out had fell out, no one seems to be able to locate the problem.
Sunday, August 28th, 2022 AT 1:45 PM

7 Replies

Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,176 POSTS
Hi,

When driving, do you ever notice the sound (to some degree) when making turns? I ask because it could be an axle bearing going bad. However, they usually will make a howling noise to some degree when turning or driving.

If possible, record the sound and upload it for me to hear. Hopefully, I will be able to identify it.

Also, have you checked to make sure the fluid is full in the differential? There is a fill port on it. It's on the passenger side inner portion of the differential housing. Usually, all you need is a 3.8" ratchet to open it. The gear oil should be to the bottom of the opening when the fill plug is removed. If you haven't, check that. See pic below

Let me know.

Take care,

Joe

See pic below.
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Sunday, August 28th, 2022 AT 9:08 PM
Tiny
PJW1977
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  • 7 POSTS
No other unusual noises any other time I did record it, but it’s so much worse in person.
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Friday, September 2nd, 2022 AT 11:41 AM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,176 POSTS
Wow! I heard it. It actually caught me off guard. I can't imagine what it sounds like in person.

I listened to the video several times. It almost sounds like a thin piece of metal. Check to see if there is a heat shield or any shield that may be moving and hitting the drive shaft. Also, some of these had a carrier bearing and a two-piece drive shaft. If your vehicle has that, make sure there is no excessive play in it.

If it was in the differential, I would expect a deeper sound. But again, it's like you said. It sounds different in the video.

Let me know.

Joe
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Friday, September 2nd, 2022 AT 8:48 PM
Tiny
PJW1977
  • MEMBER
  • 7 POSTS
I’ve had two people get under it and look for anything out of place or lose, both said they didn’t see anything. So far it only does this on the little side road that I go to work on, I am always driving 20 MPH or under when it happens, it started doing this about a week or so ago. Thank you for your help!
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Friday, September 2nd, 2022 AT 10:27 PM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 54,137 POSTS
I would not drive it anymore, that is a wild noise. Let's remove the rear tire and follow this video to see what you can find. Please upload images of anything that is found.

https://youtu.be/uo1RnATyEok

Please run down this guide and report back.
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Saturday, September 3rd, 2022 AT 7:34 AM
Tiny
PJW1977
  • MEMBER
  • 7 POSTS
It’s the only thing I have to drive, and I have to go to work. I wish I had another option.
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Saturday, September 3rd, 2022 AT 10:44 AM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,176 POSTS
Hi,

The good thing is Ken agrees that it doesn't seem to be the differential. However, the idea that we are not sure what it is at this point is why he is suggesting not to drive it.

Are you able to follow the link he added?

Joe
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Saturday, September 3rd, 2022 AT 10:35 PM

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