2021 silverado 1500 rear tires randomly lock up and skid tires at highway speed

[Curtis Atkinson]

1 hour ago, newdude said:

You are gonna get a new valve body:

 

21-NA-275: Rear Wheel Lock Up, ABS Event, Loud Bang and a Flashing “D” on Driver Information Center (DIC) when Lightly or Moderately Accelerating Forcing an 8-7 or 8-6 Downshift 

 

 2020-2021 10 speed

 

Condition

Some customers may comment on the following conditions while lightly to moderately accelerating, forcing an 8-7 or 8-6 downshift between 64-96 km/h (40-60 mph) with the transmission at operating temperature:

 

Rear wheel/tire lockup or an ABS event

Loud bang

Very hard 8-7 or 8-6 downshift

Feeling of hitting a large pothole or large speed bump

Flashing “D” on the DIC

 

Cause

This condition may be caused by an internal control valve body issue.

 

Correction

Replace the valve body assembly. Refer to Control Valve Body Replacement in SI.

Thanks for sharing. Is this a fairly easy and inexpensive repair? This must take a toll on the entire drivetrain and could cause alot more damage if not taken care of quickly i assume?

[newdude]

5 minutes ago, Curtis Atkinson said:

Thanks for sharing. Is this a fairly easy and inexpensive repair? This must take a toll on the entire drivetrain and could cause alot more damage if not taken care of quickly i assume?

 

 

Its around $1400 usd for parts and fluids.  4.5 hours labor.  There is programming involved as well.

 

I'd like to assume you are under warranty still being a 2021?  Unless you are out by mileage.  

[Curtis Atkinson]

1 minute ago, newdude said:

 

 

Its around $1400 usd for parts and fluids.  4.5 hours labor.  There is programming involved as well.

 

I'd like to assume you are under warranty still being a 2021?  Unless you are out by mileage.  

I believe i still do i dont remember what the powertrain mileage was i have 82,000km and id have to find my paper work but i think i have 100,000km powertain warrenty 

[BIGDOGx]

42 minutes ago, newdude said:

 

 

Its around $1400 usd for parts and fluids.  4.5 hours labor.  There is programming involved as well.

 

I'd like to assume you are under warranty still being a 2021?  Unless you are out by mileage.  

Of course they would stick it in a tsb and make owners have to go through locking up their back tires driving 50+ on the highway, and then play the what is wrong game with their dealers! A safety recall which is what this should be, would then make GM notify and cover the cost for customers!

[richard wysong]

That is why it is important  to notify NHTSA because they can force GM to issue a recall. GM won't do it on their own

[Steve Macedo]

On 3/2/2023 at 10:26 AM, newdude said:

You are gonna get a new valve body:

 

21-NA-275: Rear Wheel Lock Up, ABS Event, Loud Bang and a Flashing “D” on Driver Information Center (DIC) when Lightly or Moderately Accelerating Forcing an 8-7 or 8-6 Downshift 

 

 2020-2021 10 speed

 

Condition

Some customers may comment on the following conditions while lightly to moderately accelerating, forcing an 8-7 or 8-6 downshift between 64-96 km/h (40-60 mph) with the transmission at operating temperature:

 

Rear wheel/tire lockup or an ABS event

Loud bang

Very hard 8-7 or 8-6 downshift

Feeling of hitting a large pothole or large speed bump

Flashing “D” on the DIC

 

Cause

This condition may be caused by an internal control valve body issue.

 

Correction

Replace the valve body assembly. Refer to Control Valve Body Replacement in SI.