Rear End Clunk Sound

[MickeyD]

Hi all, new here.

On my 09 Tahoe, I've noticed an intermittent noise which seems to be coming from the rear end at low speeds. It seems to show up when I'm slowing down to a stop or accelerating from zero. I've tried letting off the gas a bit on accelerations, and this definitely helps mitigate the sound. But, it seems like it's not always there (I can't reliably replicate it all the time).

It seems there could possibly be correlation with the temperature; I've really only noticed the noise before the engine's up to temperature (shortly after I leave).

I know it's not something like a bad engine mount, as I replaced them a few thousand miles ago. It feels like the sound's coming from the rear axle, rather than the transmission. My thought would maybe be something with the diff, or maybe the rear suspension. I suppose, though, it's possible it's something with the tranny or torque converter.

So before I begin digging around, I just wanted to see if this may be a common, known thing, or if anyone has some good advise to help troubleshoot this. Thanks!

 

[wjburken]

Hi all, new here.

On my 09 Tahoe, I've noticed an intermittent noise which seems to be coming from the rear end at low speeds. It seems to show up when I'm slowing down to a stop or accelerating from zero. I've tried letting off the gas a bit on accelerations, and this definitely helps mitigate the sound. But, it seems like it's not always there (I can't reliably replicate it all the time).

It seems there could possibly be correlation with the temperature; I've really only noticed the noise before the engine's up to temperature (shortly after I leave).

I know it's not something like a bad engine mount, as I replaced them a few thousand miles ago. It feels like the sound's coming from the rear axle, rather than the transmission. My thought would maybe be something with the diff, or maybe the rear suspension. I suppose, though, it's possible it's something with the tranny or torque converter.

So before I begin digging around, I just wanted to see if this may be a common, known thing, or if anyone has some good advise to help troubleshoot this. Thanks!

Welcome to the forum. A lot of smart and helpful folks on here.

Could be something as simple as the spline shaft going into your rear differential sticking. Might try and get some grease on it.

Others may have some other things for you to consider.

 

[Big Mama]

When was the rear diff fluid changed? Do you notice it when you let off the gas to coast but pick up the throttle again?

 

[MickeyD]

Thanks for the replies!

So the car's at 144k, I got it at about 130k. I haven't changed the diff fluid, and I don't have a known service history. From doing a bit more digging, I'm starting to think it's either the u-joints on the drive shaft going bad or the diff having too much backlash.

If it's a backlash issue, does it make sense that changing the fluid now wouldn't do much for the situation? As for the suggestion of greasing the spline shaft, is there an existing fitting there, or is it more involved a process?

 

[petethepug]

There’s no service point or zerk fitting to lube the splines on the shaft. Just had mine apart and greased again after 30k. That means my 08 Denali lasted almost 5 years and 30k+ miles til it was due again. Buh bye clunk for a few more years.


Sent from my iPhone using Tapatalk

 

[Big Mama]

As Pete stated that clunk and changing the rear diff fluid including conditioner makes a big difference.

 

[OR VietVet]

When buying a used rig I have ALWAYS went in and changed all fluids and filters when I did not know the history. I always want to get a baseline for all that. If I was really motivated I always changed the plugs and wires as well. I trust what I do to my rigs but have a real hard time trusting anyone else. My OCD kicks in with a used vehicle. By the way, welcome to the forum from Oregon.

 

[Meccanoble]

I wont change all the fluids right away but I would inspect and change anything that didnt look confidently clean (red tranny fluid, clear/red power steering, real light oil, strong colored coolant). If anything looks like it has not been changed in a while, I change.

 

[OR VietVet]

But, even the wrong fluid can look clean. I just spent good money on a used rig and I trust only me. Whatever works for anyone else is all good.

 

[Elmo]

Hi all, new here.

On my 09 Tahoe, I've noticed an intermittent noise which seems to be coming from the rear end at low speeds. It seems to show up when I'm slowing down to a stop or accelerating from zero. I've tried letting off the gas a bit on accelerations, and this definitely helps mitigate the sound. But, it seems like it's not always there (I can't reliably replicate it all the time).

It seems there could possibly be correlation with the temperature; I've really only noticed the noise before the engine's up to temperature (shortly after I leave).

I know it's not something like a bad engine mount, as I replaced them a few thousand miles ago. It feels like the sound's coming from the rear axle, rather than the transmission. My thought would maybe be something with the diff, or maybe the rear suspension. I suppose, though, it's possible it's something with the tranny or torque converter.

So before I begin digging around, I just wanted to see if this may be a common, known thing, or if anyone has some good advise to help troubleshoot this. Thanks!