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Harmonic resonance from exhaust

PG73

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PG73 Enthusiast

PG73

Posted
Posted

I have a 2015 Sierra 2500 with a vibration in the steering wheel when the rpm is around 2100. The truck can be in park and still vibrate when revved up to 2100. Took to the dealership and they put a picoscope on the truck and it shows that the exhaust is causing the vibration. The vibrations are within in spec so gm says there is no problem. They say all of there engines do this but mine is just a bit worse. When towing or accelerating in corners if is strong in the steering wheel and you can here the vibration. Doesn't seem normal to me.

 

Anyone else have this problem?

chuckl1218 Senior Enthusiast

chuckl1218

Posted
Posted

There have been a lot of vibrations reported here due to the exhaust adaptive valve. One way to test for this is to force it open during your test by either using a hose clamp on it or a bolt through it to hold it open. Some have had to have their exhaust replaced due to this issue. Not sure if it is the same, but...

Cosmic Charlie Enthusiast

Cosmic Charlie

Posted
Posted

My truck has it ... others here have talked about it ... some dealer was trying to find the reason and I never heard back from the original poster ...

 

it's a slight vib / almost a quiet moan you can feel - at about 2200 under light acceleration thru the fire wall / steering shaft area (very minor but there briefly)

 

I'm not worried about it

 

see below:

 

http://www.gm-trucks.com/forums/topic/180278-vibrations-in-new-2015-sierra/

Frustrated2 Enthusiast

Frustrated2

Posted
Posted

My 2015 Sierra 6.2 2wd also has a vibration. haven't noticed the rpm but it usually occurs under very light or no acceleration at between 40 and 50 mph. Sometimes it is so bad that it feels like driving on washboard roads. Other times it is quite light.

 

I also have a shudder during the shift between 2nd and 3rd gears. There was a recall on this issue and the computerized shift points were reprogrammed. It helped but has not totally resolved the problem.

 

I love the power this truck has and the looks of the truck itself but I'm quite concerned about the longevity of the transmission. G.M. has a long history of putting vehicles on the road that aren't ready. I'm afraid their new 8 spd. transmission is another case in point.

 

I have read other contributions about exhaust harmonics causing the vibration but I don't believe you would feel this thru the steering wheel like a transmission issue. May never know.

07Softail Senior Enthusiast

07Softail

Posted
Posted

I haven't heard of any GM recall of reprogramming shift points can you elaborate on this. Even with a tune I did it hasn't fixed my 2-3 shift flare.

 

RT

EastCoast HD Enthusiast

EastCoast HD

Posted
Posted

There have been a lot of vibrations reported here due to the exhaust adaptive valve. One way to test for this is to force it open during your test by either using a hose clamp on it or a bolt through it to hold it open. Some have had to have their exhaust replaced due to this issue. Not sure if it is the same, but...

 

His truck is a 2500.

 

No EAV.

FL335i Enthusiast

FL335i

Posted
Posted

Put a magnaflow or AFE cat-back on it. That will fix it. I did a cat-back around 8k miles IIRC. Towing with the stock system was terrible. MPG's have gone up about +1 overall. Plus it sounds like a truck not a prius.

chuckl1218 Senior Enthusiast

chuckl1218

Posted
Posted

His truck is a 2500.

 

No EAV.

Whoops...missed that...sorry...I think others may too...thanks for pointing that out...

PG73 Enthusiast

PG73

Posted
  • Author
Posted

Thanks Cosmic! This other poster is having the same problem.

 

Mine is more than slight and at times quite loud. The loudest vibrations come when cornering but are not always there so it can be quite surprising when it happens. When towing a trailer the truck will want to stay around 2100 rpm so I can feel a vibration in the steering wheel mile after mile and it is very annoying. The mechanic said it is the second worse he has seen but GM wont fix it. I have left 3 messages with my GM rep and they won't call me back.

PG73 Enthusiast

PG73

Posted
  • Author
Posted

Sorry for posting in the 1500 area. I am a noob here.....

 

The mechanic did say that all the GM engines do it and he can feel it in his 5.2. maybe his is the EAV but mine is something different??

SILVER SLED Senior Enthusiast

SILVER SLED

Posted
Posted

We had one in, a 2500, with a strange resonance at 55ish mph. It ended up being the 245 tires. GM said remove 245 tires and put the next size larger on, cannot remember the exact size. Supposedly there is an unreleased bulletin.

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