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Discussion Starter #1
When I first start to drive my truck, after sitting all night, I get this whinning noise. I am not sure if it is the power steering pump going bad or if it is the turbo. What does it sound like when the turbo is going bad on a LB7? Also I can hear it when idling or driving. The noise also fluctuates with the throttle. After the truck is warm it goes away. If it is the turbo would it stop after warming up?
 

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I am having the exact same thing, Does it get worse when the brakes are applied? If so it is the power steering pump, I wouldnt think your turbo is going bad if it only does it at an idle. My noise goes away after it warms up.
I am going to try flushing my fluid and see if that affects it at all.
 

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What you are hearing is the sweet sound of the Allison,its the oil lift pump in the transmission,all the Allisons do it till they get warm.Normal
 

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I agree. Mine does this all the time, just about every morning when it is slightly cooler outside than normal. Usually goes away after about 10 miles or so...
 

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Damn, thought I was the only one with this and thought my SC5 was on it's way out. Started doing it off/on this winter ... at first I thought it was the turbo as well. MaxPayne set me straight on the tranny pump ...still weird though. Never did it last winter.
 

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Discussion Starter #6
The thing is this is coming from the engine bay. I can still here my allison doing its usual thing that sounds more like a blower or something. This just started up with in the last month.
 

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does it sound like an old school fire engine siren? wooooooooooo woooooo type noise? if it is its the bearings failing in the turbo. if you baby it you can go for a while. i had a noise that sounded like that and it was the turbo. around 3psi it would get loud but the truck still ran pretty much the same. i didnt believe that was the problem because it would quiet down the warmer the temp was outside. i found out at the drag strip that that was the problem (kaboooooooom). glad it happened there, would not have been fun trying to get the truck shut down on the side of the road.
 

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Discussion Starter #8
Well it doesn't sound like that. It must either be the power steering pump or the tranny.
 

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The turbo isn't doing anything at an idle. Well, maybe spinning a few RPM's, but nothing significant.
 

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Well it doesn't sound like that. It must either be the power steering pump or the tranny.
probably is, you cant hear what i described at idle.
 

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The allison whin wont be heard at idle, only when you increase rpm.
 
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