Trying to diagnose a sound related to my 2016 Chevy Silverado 2500HD 6.0 4x4.35mph low throttle (1200-1500rpm) input uphill occasionally get a grinding sound that resonates back into the gas pedal.Doesn't sound like a u-joint, rear diff spider gears, wheel hub, or cv axles. Sound come from below the drivers seat.
The grinding isnt a high pitch grinding sound or like gear slipping. It's metal on metal like the wear indicator on a brake pad.Finding somewhat similar issues online but the only ones that somewhat relate (but dont) point to the transfer case or torque converter.
Sound does not occur if I accelerate with some authority but if I baby it then it will grind as I give it more throttle to get up the hill.
I notice the Sound going downhill decelerating earlier but i havent been able to recreate that one. Just up hill.

Any thoughts on what it could be?

 

Could be a lot of things.
You can gadgets online for around $70 that let you listen in to different parts of your vehicle, and help pinpoint it.

 

Ever figure anything out? I am having what I believe is the same problem with my 2014 1500 Silverado. It is a strange chatter noise that only happens at low rpms. Doesn’t necessarily affect anything that I know of. It just sounds terrible when pulling out of a parking lot or pulling away at a stoplight. Doesn’t happen all of the time but it does happen.

 

I'm experiencing a very similar issue with 08 6.6. It started as making the noise when I'd hit a hard bump. Now it's doing it as i accelerate sometimes. Very intermittent, cannot figure out a pattern. Did you ever figure out your issue? It also must be causing a drag on the electrical system because my battery voltage drops from 14V to around 11V when the problem occurs and all my lights dim.

 

From the description you gave. watch the torque converter slip speed and see if the grinding/ vibration occurs with tcc application. Usually can get to happen when trans is warm, about 40-50 mph and light acceleration or pulling a light grade. I'm assuming you have a 6 speed trans. the torque converter chatters and sets up a vibration through the rear drive shaft. Can check the trans fluid to see if there is any metal on the dipstick. With not hearing the noise this is something to look at and is something I have seen many time in the past, and hope it helps.

 

Did you ever fgure out what the sound was. I believe im having the same issue and cant find exactly where its coming from.