What's with the vibration in these trucks with 6.2/8 speed

[Bhiland122]

I've seen several posts in different places about this. My truck is doing it more as it goes. More often when I'm feather the pedal to keep up with traffic around 60mph but it has done it when I'm on city street at 15 and just barely gassing it. I notice it more when in cruise control on certain highways in my area that are hilly. It starts the vibration and then let off pedal and it instantly stops so I know it is something. Some times you can hear the vibration. Metallic zing. I'm tired of it. The steering wheel vibrates in my hand. Steering vibrates like crazy to where you can actually see it vibrating like a sex toy. But if I stay in the pedal more than just a feather it doesn't happen from what I can tell. Anybody got info on this? 2015 gmc sierra denali

[scott19677]

Kind of confusing with your descriptions. Is the truck vibrating or is the engine vibrating? There is a vibe topic on here that is probably up to about a million pages now and I don't want to even start trying to explain if that is your issue. Lets just say you have a lot of reading to do. But you mention it is related to engine load and you can actually "hear a metallic zing". So there are a few things that come to mind.

 

Possible problem with your torque converter, AFM not operating properly, check all your spark plug wires for a good snug fit, engine mounts have been know to be a problem on some of the early K2's and need to be shimmed but that was mostly on 14's I think. Check your flapper valve in the exhaust. I could go on and on but really you need to narrow it down a little.

 

So... try this. Drive the truck in manual mode. By this I mean instead of putting your trans shifter in D, put it in M5. This will lock out the AFM and keep the truck operating on all eight cylinders.

Sounds to me like you drive with a light foot and your truck is going in and out of V4/8 and you are reacting to it and with the piss poor factory tune on the TCM on these trucks your transmission is getting "confused" for lack of a better word. But this is a good place to start without having to get your hands dirty. And don't feather the throttle so much for God's sake. Throw the coals to it every once in a while.

 

So....? play with a lot of sex toys do 'ya?

Just kidding. Good luck and keep us posted.

[muddkatt]

Take it to the dealer, that is what the warranty is for.

[seamus2154]

The three main issues most complain about are this:

 

V4 mode , exhaust vibration and sound --- give it gas and it goes away. Alot of people feather the gas staying in and out of this mode driving themselves crazy!

Shuddering in 2014-2015 models which is the bad Torque converter

And the biggest one is the horrible cheap tires causing vibrations. I had this same issue on three trucks and they changed over 15 tires on all three vehicles till i paid for Michelins on my present ride and vibrations disappeared!!

[seamus2154]

Kind of confusing with your descriptions. Is the truck vibrating or is the engine vibrating? There is a vibe topic on here that is probably up to about a million pages now and I don't want to even start trying to explain if that is your issue. Lets just say you have a lot of reading to do. But you mention it is related to engine load and you can actually "hear a metallic zing". So there are a few things that come to mind.

 

Possible problem with your torque converter, AFM not operating properly, check all your spark plug wires for a good snug fit, engine mounts have been know to be a problem on some of the early K2's and need to be shimmed but that was mostly on 14's I think. Check your flapper valve in the exhaust. I could go on and on but really you need to narrow it down a little.

 

So... try this. Drive the truck in manual mode. By this I mean instead of putting your trans shifter in D, put it in M5. This will lock out the AFM and keep the truck operating on all eight cylinders.

Sounds to me like you drive with a light foot and your truck is going in and out of V4/8 and you are reacting to it and with the piss poor factory tune on the TCM on these trucks your transmission is getting "confused" for lack of a better word. But this is a good place to start without having to get your hands dirty. And don't feather the throttle so much for God's sake. Throw the coals to it every once in a while.

 

So....? play with a lot of sex toys do 'ya?

Just kidding. Good luck and keep us posted.

This is all good info and dead on. I forgot they did do an updated tune on my trans control module after my TC replacement and it was an improvement.

[Lgetz]

Sounds like the torque converter is acting up. Take to the dealer they will probably first do an update but this is not the solution. After a new converter, a further update and change of transmission fluid all has been well for the past nearly 5K miles.