• Welcome to The Truck Stop! We see you haven't REGISTERED yet.

    Your truck knowledge is missing!
    • Registration is FREE , all we need is your birthday and email. (We don't share ANY data with ANYONE)
    • We have tons of knowledge here for your diesel truck!
    • Post your own topics and reply to existing threads to help others out!
    • NO ADS! The site is fully functional and ad free!
    CLICK HERE TO REGISTER!

    Problems registering? Click here to contact us!

    Already registered, but need a PASSWORD RESET? CLICK HERE TO RESET YOUR PASSWORD!

LML: Funny Noise

The buzzing, sounds like my old AirDog pump but I don't have one on here.
 
I'm not quite sure how GM operates there SCR systems... but the way it works on Cummins engines (ISB / ISC / ISL CM2250), has several stages of the SCR system. 2 of them are Prime and Purge. Prime runs the DEF pump to "prime" the system up to the DEF dosing nozzle, and this will occur upon key-on. Purge, which occurs at key-off, switches the ...sector valve... I believe its called, and sucks the DEF lines empty and returns it all back to the tank. What your hearing may be the SCR system priming. Though its hard to say without understanding how GM operates there SCR system. Like I said, this is how Cummins does it, for all i know GM may just leave the DEF in the lines all the time. :eek:
 
After thinking and re-reading this, is there any chance that it could be coming from the Allison? When it is COLD out, the Allison's (Mine is a 2006 LLY 6 speed) make some crazy noises as the fluid is being pumped through. Buzzing, hissing, groaning etc., until it warms up a little. Then it goes away completely. Maybe it is just the cold fluid going through the Allison, before it warms up? I do not have any emission extras such as DEF or SCR to base the sound on.
 
Here in SETX it normally doesn't get too cold and on the '06 Alli 6 spd I had I never heard any noises from the trans. This sounds like the AirDog I had but louder. I seem to notice it the most on first start of the day. I checked the power steering fluid and the level is good. I'm getting the "Reluctant temp" code P205B sometimes on first start of the day too but I don't think these are related.
 
I think I found my mystery noise:

GM Document: PIP#4898

Video of Said Noise:

http://www.youtube.com/watch?v=LwP05bolnjg&feature=youtu.be

It appears an upgraded oil pump will correct the issue. However, no harm is done leaving the "noisy" one on from what I'm reading. My only reasoning for not taking it in is the teardown to get to it. I'd rather not cause any issues because of a simple noise.
 
Not to go off-topic, but good to see you back around Ed. Looking at your sig, what happened to your 06?
 
Dad's 05 LLY said:
Not to go off-topic, but good to see you back around Ed. Looking at your sig, what happened to your 06?
Click to expand...

Thanks...it was hit and totaled :( I really liked that truck! Still adjusting to the replacement.

Back on topic...BoostN that is the same sound I hear but it is only first start of the day after it has ran for sometime it goes away. When I get back home next month I'll talk to the dealer about my P205B and ask about the oil pump you mentioned. BTW do you have a link to where you read this?
 
I'll find it an post it for you.

Sent from my HTC One using Tapatalk
 
Thank you. I didn't read the whole thread just from where your link started. I need to check with some dealers and see if they know anything about this.
 
You must log in or register to reply here.
Back
Top