Help diagnose grinding noise when high rpms.

[Kap1]

Hi All,

I got a 2013 Big Horn QC 4x4 5.7 with 36k miles. Here's another one of my many issues with my truck...

As soon as i got my camper shell installed 2 years ago, i began hearing more noises from my rear window as they now amplify better through the gap between the cab and the bed, and go right into my back window. If i didn't have the camper shell, i would never ever heard this slight noise.

When i'm getting onto the freeway or accelerating up the hill, i hear these Brief grinding noises from my back window. It usually happens when my RPM's are above 3-4k , in the 30-60mph or so, and in Majority of times, these brief grinding noises are heard right before truck shifts the gears to go faster. This noise only occurs when i'm driving, if i rev engine in Neutral it's not there. The noise only happens when i'm in Moderate acceleration and stressing the truck a little bit (e.g. accelerating up the hill onto the freeway ramp with 3-4k rpm speed).

These grinding noises are pretty brief and pretty quiet, and it's hard to hear them when other normal road noises are there as well...

I did mention this to my dealer couple of times on different visits, but they "can't hear it" . I even test drove with their Foreman once, but it was hard to reproduce these noises because i needed to do moderate acceleration onto the freeway without any traffic ahead of me... So the Foreman did not hear the noises since they were too quiet.

1. Any easy way to diagnose these noises to narrow down the issue?

2. What could it be based on my description?

Thank you all in advance! Glad to be part of such great community.


https://youtu.be/eZ7ywqy7Z2E

 

[Saltillo Express]

definitely a grind? no chance its something rubbing or rattling when the truck is under load (with the new topper) at that particular RPM? Just guessing...

 

[Kap1]

Honestly, not sure, it could be some sort of rattle, but sounds like a mechanical grind. I had another sound before too and after lots of diagnosing dealer traced to loose cable and fixed it but not this one..

 

[Saltillo Express]

Hmmm. Is having someone drive with you in the bed to try and hear it out of the question? Eh that's probably silly. I would just think that a grind, a metal on metal gear related grind you would hear all the time. If the brakes were dragging that can sound like a grind, but you will hear that the most at off idle. I suppose it could be an axle bearing or in the u joint or differential. What's your 20? Not in Florida are you?

 

[Kap1]

Hi all,

Bump, I found YouTube video of someone else having Exactly same noise as my truck.

Could you guys please hear the noise and offer suggestions?

Here's YouTube link https://youtu.be/eZ7ywqy7Z2E

Thank you! Hope I can get dealer to fix it now finally!

 

[Saltillo Express]

That is damn weird. One thing I noticed is each time it goes to rattle - it's immediately followed by a scraping sound. Sure seems like it's right there. Good luck.

 

[Rustycowl69]

if there isn't something rubbing on the driveshaft, and there isn't some piece of shielding or some other piece of tin vibrating, then I might try pulling the driveshaft. Check the u joint caps, and trunnions , and also make sure there isn't some debris inside the driveshaft.