V4 to V8 mode squeak

lockey14s · May 15, 2014

Bought a brand new 2014 ext cab LT with the 5.3 back in february. Now that its getting nicer and have had the windows down more often i have noticed a faint squeak every time I accelerate and it goes from V4 mode to V8.

I cant really pin point the location since it only happens when im driving but it sounds like its from the rear. My only guess is it could be the butterfly valve after the muffler opening up when it gets more pressure from the exhuast...

Anyone else noticing this? its just one of those things that is really bugging the crap put of me. other than that the truck is awesome!

chuckl1218 · May 15, 2014

Common issue with the adaptive valve. Look for it in the exhaust threads.

lockey14s · May 15, 2014

cant seem to find anything... but it is that valve?

losky79 · May 15, 2014

http://www.gm-trucks.com/forums/topic/153020-exhaust-adaptive-valve/

A quick way to find out if it is the exhaust valve located behind the rear of the muffler is to place a hose clamp over it in the open position then drive your truck and see if it still makes the noise you are hearing.

20L8TSierra24 · May 15, 2014

http://www.gm-trucks.com/forums/topic/153020-exhaust-adaptive-valve/

A quick way to find out if it is the exhaust valve located behind the rear of the muffler is to place a hose clamp over it in the open position then drive your truck and see if it still makes the noise you are hearing.

Rotate the valve counter clockwise and clamp. This gets rid of turbo whistle sound some are having as well as squeak from v4-v8. I clamped mine Monday and haven't heard a squeak since.

Trackermi · May 16, 2014

Rotate the valve counter clockwise and clamp. This gets rid of turbo whistle sound some are having as well as squeak from v4-v8. I clamped mine Monday and haven't heard a squeak since.

Same thing here. I did it as a test and the noise was removed. I put mine back for now. Curious on the effect on overall engine responsiveness and MPG. Not sure it matters much but mine seems to shift into V8 better without the valve. I know sometimes it seems like it gets stuck and the truck runs like crap.

lockey14s · May 16, 2014

http://www.gm-trucks.com/forums/topic/153020-exhaust-adaptive-valve/

A quick way to find out if it is the exhaust valve located behind the rear of the muffler is to place a hose clamp over it in the open position then drive your truck and see if it still makes the noise you are hearing.

I did the muffler delete a couple weeks back and was considering taking the valve out also, but I heard it helps a lot with the V4 drone. I will try the clamp open and see how it sounds. It will probably help with the exhaust tone when its at idle too, right now it just sounds like rushing air.

oakleyguy · June 2, 2014

I just got my truck back from the shop for this reason. They just replaced my exhaust with a "redesigned" muffler to stop the squeaking.

fondupot · June 2, 2014

Clamped my valve open a few months ago. No more flappy flap noise

ZeKeef13 · June 14, 2017

I just got my truck back from the shop for this reason. They just replaced my exhaust with a "redesigned" muffler to stop the squeaking.

Did this fix the noise? And has it since came back?

ZeKeef13 · June 14, 2017

Clamped my valve open a few months ago. No more flappy flap noise

How exactly are y'all clamping the valve? Also does it effect the MPG and exhaust sound?

sk · June 21, 2017

Did this fix the noise? And has it since came back?

I had this done to mine. It's not a redesigned muffler -- it's a redesigned Passive Exhaust Valve and it's also located BEFORE the muffler on the new design. Yes it eliminated the squeak.