PackerChev

I just stumbled across a response that seems like there could be some logic to... After numerous rides to the dealer and talking to several techs, one answer finally made sense. The valve package of the transmission is located on the drivers side. These 6-speeds are super smart, and when the truck is under lightacceleration, in a high gear like 6th, basically lugging, the transmission starts to preload the gears for optimal gearsection. You can hear right before the shift the clicking of the solenoid valves in the transmission. It is completely normal. I've always thought that there seemed to be a correlation between the ticking and the tranny. It seems like it’s in the drivetrain and not so much the motor because it doesn’t do it when you rev the engine and it directly correlates with the RPMs.

Hardest noise in the world to figure out! I’ll buy a case of busch light for the guy who figures it out!

So the vacuum pump replacement did not fix the noise?

Has anyone found a fix for this issue? I crawled under the truck and it sounds like it comes from the catalytic converter right off of the header manifold. I've also read somewhere that there is a ceramic piece inside the converters that causes it. This would make sense that it is temperature dependent and can change when you hit a bump of go around a corner. I've got a 2017 Silverado. It doesn't do it when cold. Once it's warmed up it does it intermittently. It's most noticeable under load and slight acceleration. Kind of just living with it for now until I can direct the dealer in the right direction because it's so hard to replicate and it doesn't appear there is a fix. The video on this thread is the spot on sound I have.

2017 Silverado Rally 2 (decals removed)