2020 Silverado 6 speed issues

[R J]

Hey everyone,

 

I just purchase my first Chevy (2020 Silverado Trail Boss Custom 5.3 6 speed). The truck has been amazing so far. I am having an issue with the 6 speed though. When braking hard, the truck clunks. I have no clue what this issue can be. Has anyone had this issue before? Are the 6 speeds reliable?

[CamGTP]

Are you sure it's transmission related??

 

The 6 speeds can have a downshift clunk or lurch feeling sometimes at slower speeds but there really isn't much you can do about that. Sometimes it can come down to how the person drives their truck and how the adapting learning works with that.

 

Otherwise the 6 speed is a solid transmission, it's been around for 13+ years now with many improvements to it's design since 2006-2007.

[Grumpy Bear]

51 minutes ago, R J said:

Hey everyone,

 

I just purchase my first Chevy (2020 Silverado Trail Boss Custom 5.3 6 speed). The truck has been amazing so far. I am having an issue with the 6 speed though. When braking hard, the truck clunks. I have no clue what this issue can be. Has anyone had this issue before? Are the 6 speeds reliable?

When braking hard. There is  your clue. Drivelines have some play. It's required. Ever hear a string of box cars string up stopping? Just taking out thy slack. 

Edited October 17, 2020 by Grumpy Bear

[flyingfool]

when did GM stop putting in 6 speeds into thier trucks? i thought 2020 models got an 8 or a 10 speed

 

i personally found if I have to brake hard, I will shift into Neutral as this shortens my hard braking distance and it seems to add a little more rear brake bias too, go figure.  the internal mass on the 6 speeds is a power hog compared to the older 4 speeds, not to mention the new 8- or 10 speeds, they can suck a ton of hp . but give it a try next time to see for yourself. using manual 4/5th gear also reduces clunk on my truck

Edited October 17, 2020 by flyingfool

[CamGTP]

The work trucks and custom trims can still get the 6 speed auto.

[Silverado4x4]

6 hours ago, flyingfool said:

when did GM stop putting in 6 speeds into thier trucks? i thought 2020 models got an 8 or a 10 speed

 

i personally found if I have to brake hard, I will shift into Neutral as this shortens my hard braking distance and it seems to add a little more rear brake bias too, go figure.  the internal mass on the 6 speeds is a power hog compared to the older 4 speeds, not to mention the new 8- or 10 speeds, they can suck a ton of hp . but give it a try next time to see for yourself. using manual 4/5th gear also reduces clunk on my truck

Yeah ok, if anyone has to brake hard the last thing on there mind is shifting into neutral.

[newdude]

6L80/90 have done this since 2007.  Normal.  

[flyingfool]

3 hours ago, Silverado4x4 said:

Yeah ok, if anyone has to brake hard the last thing on there mind is shifting into neutral.

it works, just separating the engine from transmission durring braking, reduces the push of the engine at 1000 rpm on the drive line, even though its not under load. try it. just dont put it in Reverse...lol

[R J]

Thank you for the replies. It’s good to know that it isn’t an issue. How long do the 6 speed transmissions typically last? 

[CamGTP]

As with anything mass produced it's hard to say. The vast majority of trucks are going to see well over 100,000-125,000 miles without a major problem.

[Frankielozano214]

7 hours ago, flyingfool said:

it works, just separating the engine from transmission durring braking, reduces the push of the engine at 1000 rpm on the drive line, even though its not under load. try it. just dont put it in Reverse...lol

not responsible for damages if put in reverse  

[flyingfool]

i found it interesting and have no idea why, but by shifting to neutral  on a 1500 truck , I actually gained more "rear brake bias" durring a stop. I wish i knew more about the brake proportioning system on these truck, 'cause the nose dive brake effect is not ideal. i wish it could be modified somehow

Edited October 18, 2020 by flyingfool

[swathdiver]

5 hours ago, R J said:

Thank you for the replies. It’s good to know that it isn’t an issue. How long do the 6 speed transmissions typically last? 

The first sign of trouble usually occurs around 160K miles when the solenoids need to be rebuild in the TECHM and this can be done on your kitchen table.  Change the fluid before 50K and it will last a long long time.  Not sure about the T1s, the K2s introduced a thermostat to keep the fluid temp at 195 like the coolant, bad for long life, get rid of it if you can.

13 minutes ago, flyingfool said:

i found it interesting and have no idea why, but by shifting to neutral  on a 1500 truck , I actually gained more "rear brake bias" durring a stop. I wish i knew more about the brake proportioning system on these truck, 'cause the nose dive brake effect is not ideal. i wish it could be modified somehow

On my 900, there is a place in the computer to enter the kind of tires you are running.  A technician on here said it was to adjust how the brakes operate if I remember correctly.  Using a Tech-2, it knows it has Load Range C tires and at what air pressure and the truck stops on a dime, about 130 feet or so from 70.

[Grumpy Bear]

1 hour ago, swathdiver said:

The first sign of trouble usually occurs around 160K miles when the solenoids need to be rebuild in the TECHM and this can be done on your kitchen table. 

 

YIKES, I'm only 30K from issues? 

That's less than a year away!

Edited October 18, 2020 by Grumpy Bear

[flyingfool]

13 hours ago, swathdiver said:

 

On my 900, there is a place in the computer to enter the kind of tires you are running.  A technician on here said it was to adjust how the brakes operate if I remember correctly.  Using a Tech-2, it knows it has Load Range C tires and at what air pressure and the truck stops on a dime, about 130 feet or so from 70.

i would like to find out more info on this, is there a gm tech bulitin  or tech documentation?

 

not even considering panic stop but just regular daily stop and go action,  neutral shifting makes the truck feel effortless entering the stop and more relaxing, then when in  Drive and having the engine pushing the driveline

Edited October 18, 2020 by flyingfool