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: An interesting noise


Dubel A
09-27-2009, 06:31 AM
Okay
I dont know how to spell sounds
My truck is making a sound, oh, you need something more specific you say.
Here we go.
At low RPM, maybe around 800-900 my truck makes this noise. It is not only audible outside my truck but inside as well. It is not a vibration although it is such a low tone that it makes windows shake in parking lots and anything on my bed vibrates.
I have never been able to make the noise at an idle while playing with the throttle, in only does it while in gear, either forward or revers. It dosent always do it and it is not predictable.
I can never assume the noise will be made in the same situation it was the last time.
It does tend to do it under light or no load, never under heavy load.
It seems to be exhaust...something.
What I am trying to describe is the note of the exhaust changes......ALOT.
This noise has been going on for some time now and had never been a concern as I had always herd the noise, at least as long as memory serves I have herd the sound.
The only reason I bring it up now is today, while under a significant load, my truck was, different. Cant explain it, it was just different.
So, any ideas, anyone.
Just a standard LLY
K&N
4" T-back exhaust
Regular pump fuel with PowerSource additive

Additionally, another thing my truck has always done, is while sitting at idle, my exhaust note will change. No RPM change, but it almost sounds like the turbo is spooling up, goes for 5-10 seconds and the 'low whistle' stops.
A buddy of mine suggested waste gate, but I didnt think the LLY had one?
I dont know if the two are connected or not.

I have never had a single issue with the motor.
Regular oil and fuel filter changes.
The only problems this truck has had are due to me. U-joints, bearings, total break failures, fenders, things like that. The engine is a stud, it is the one thing on the truck I really never think about.

KevinsDMAX
09-27-2009, 07:51 AM
Not sure about your first sound, but the other one is your turbo. I had the same question when I put on my CAT delete pipe. What you are hearing is the vanes of your turbo changing.

Good luck on your first noise.

Kevin

Dubel A
10-02-2009, 09:13 PM
Regarding the 1st noise, I typed the wrong RPM in there, it happens at 1100 RPM.
I have no trouble codes, and most everything seems to be the same as it has always been, although it has seemed to be getting louder.
Regarding the second noise
I was sure it was the turbo, my question is, why would it spool up like that under no load and maybe most importantly, is my turbo going out?

Could the 2 noises be linked?

Dubel A
10-03-2009, 08:21 PM
So nobody here has any idea what it might be?
I figured this to be the end all be all of Durmax websites!

jollyrogr
10-03-2009, 09:25 PM
Your turbo is not going out. It's normal to cycle vane positions at idle - hence the changes in exhaust note.