2020 Sierra 1500 Friction/Grinding Noise

[GMCDenaliLife]

Hi All,

 

First time poster so I apologize if this isn’t the right spot of this question. 
 

I have a 2020 Sierra 1500 with just over 27,000 miles and in the last 6-8 months every time I decelerate (coast and brake) between 15 and 30 miles I hear a audible but not enough to get on a recording grinding/rubbing noise below me. If I touch the accelerator pedal ever so slightly it goes away and you don’t hear it with highway speeds. 
 

Once I go below 14 mph it goes away. If I put the truck in neutral it also goes away or isn’t there. It also happens in 4 wheel drive. 
 

I have taken it to a mechanic and they hear nothing and everything checks out. But, this is very audible and happens every time I drive. 
 

Any thoughts? Things I’ve researched heavily leans towards transfer case issues. Also heard about U joints, CV joints, wheel bearings (shouldn’t be the cause due to the neutral test), and pinion issues. 

[GMCDenaliLife]

I stumped everyone here

[LucasCRichard]

On 9/23/2024 at 9:25 AM, GMCDenaliLife said:

Hi All,

 

First time poster so I apologize if this isn’t the right spot of this question. 
 

I have a 2020 Sierra 1500 with just over 27,000 miles and in the last 6-8 months every time I decelerate (coast and brake) between 15 and 30 miles I hear a audible but not enough to get on a recording grinding/rubbing noise below me. If I touch the accelerator pedal ever so slightly it goes away and you don’t hear it with highway speeds. 
 

Once I go below 14 mph it goes away. If I put the truck in neutral it also goes away or isn’t there. It also happens in 4 wheel drive. 
 

I have taken it to a mechanic and they hear nothing and everything checks out. But, this is very audible and happens every time I drive. 
 

Any thoughts? Things I’ve researched heavily leans towards transfer case issues. Also heard about U joints, CV joints, wheel bearings (shouldn’t be the cause due to the neutral test), and pinion issues.  poppy playtime chapter 3

I thought users would share their experiences and concerns especially about potential causes like transmission problems or worn parts, which can be difficult to diagnose.

Edited October 15, 2024 by LucasCRichard

[asilverblazer]

On 9/22/2024 at 9:25 PM, GMCDenaliLife said:

I have a 2020 Sierra 1500 with just over 27,000 miles and in the last 6-8 months every time I decelerate (coast and brake) between 15 and 30 miles I hear a audible but not enough to get on a recording grinding/rubbing noise below me. If I touch the accelerator pedal ever so slightly it goes away and you don’t hear it with highway speeds. 
 

Once I go below 14 mph it goes away. If I put the truck in neutral it also goes away or isn’t there. It also happens in 4 wheel drive. 

I think the source of the noise is the transmission. The question remains if it is normal or not. 

 

I think the very specific speed (it downshifts to a lower gear or up to a higher fear outside of the speed range you indicate) of the noise is due to the gear the transmission is in - to confirm or test, try putting the range selector in manual and when the noise is occurring select a gear higher or lower.

 

I would also suggest a fluid flush as a maintenance item - and it might help the noise too.