Vibration at 60mph

[rossgonyer]

My 2018 Sierra with 40k miles vibrates between 60 and 65 mph. I have had it balanced twice and aligned but it hasn't helped.  Can anyone shed some light on what may be going on?

[m3n00b]

2 minutes ago, rossgonyer said:

My 2018 Sierra with 40k miles vibrates between 60 and 65 mph. I have had it balanced twice and aligned but it hasn't helped.  Can anyone shed some light on what may be going on?

8 speed?

[aseibel]

https://www.cashcarsbuyer.com/chevy-shake/

 

[rossgonyer]

No.  I should have also added that its a 1500 crew cab.

[flyingfool]

it might be the freeways  your driving on. the long wheelbase syncs up with the ripples and waves. = high speed vibration.  

try going to a smog station dydno and get it up to 80mph  slowly. this will confirm the road surface is the variable

[Grumpy Bear]

4 hours ago, rossgonyer said:

My 2018 Sierra with 40k miles vibrates between 60 and 65 mph. I have had it balanced twice and aligned but it hasn't helped.  Can anyone shed some light on what may be going on?

Has it done this from new or just recently started? 

[Grumpy Bear]

18 hours ago, Grumpy Bear said:

Has it done this from new or just recently started? 

Yea, bout what I thought. 

[rossgonyer]

Fairly recently.  Im guessing that its in the transmission.

[David Wallace]

4 hours ago, rossgonyer said:

Fairly recently.  Im guessing that its in the transmission.

do you notice any type of sound? is it constant or in a rhythm?

[flyingfool]

12 hours ago, rossgonyer said:

Fairly recently.  Im guessing that its in the transmission.

I had the same issue start to vibrate at 75mph on most freeways. then I took a trip out to my local dry lake bed, its smooth as glass.... did three passes until I hit rev limiter or speed limiter. not a single bad vibration at all! it was amazingly smooth.  so that experiment put to rest any driveline vibrations for me. I recommend going to a dyno shop and try it for yourself.

Edited October 17, 2020 by flyingfool

[rossgonyer]

At this point, I'll try anything. Thanks!

[jpatt006]

What tires do you have on there?  I know a lot of guys have had luck with changing tires or getting a road force balance (myself included).