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Thread: High Pitched Whine

  1. #1
    Join Date
    Mar 2010
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    NE Tennessee
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    Default High Pitched Whine

    I have a 2008 Chevy 2500HD Duramax diesel with Allison transmission. When I am towing my 10M lb. fifth wheel camper on a steep grade, I sometimes hear a high-pitched whine after having been on the steep grade for some time. The whine goes away after I level out on flat ground. Is this normal and what is causing this extra noise?

  2. #2
    Join Date
    Feb 2000
    Location
    Montana
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    11,465

    Default

    You may be hearing the turbocharger. If you had a boost pressure gauge, you may see a correlation between the whine and boost pressure. Otherwise, you could check the sealing of the airbox, air inlet ducting and related clamps for looseness.

    Jim

  3. #3
    Join Date
    Mar 2010
    Location
    NE Tennessee
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    16

    Default Boost Pressure Gauge

    Is this an after market item?
    This is my first diesel and I have a lot to learn.
    Thank you.

  4. #4
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    Apr 2001
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    CA
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    13,639

    Arrow

    A boost gage is an aftermarket item. Not expensive, but requires some skill to install. Some kits allow for a tee to be used in a rubber line on earlier models, but yours doesn't have this option (no wastegate hose). You'll have to drill/tap somewhere in the intake charge-air side. No biggie, but no bolt-on, either.

    Probably the turbo. As you start to pull a hill, the engine is relatively cool, as is the temps underhood (including intake air). As the hill goes on, things heat up and change the way the engine (and electronics) works to accommodate this. The turbo doesn't necessarily make more noise at higher power demands, but can, and does in most cases, have a boost/RPM/load range where it's most noticeable. Mine, for example, is most noisy (sounds like an F-16 winding up) at about 2,000 RPM's and between 8 and 12 PSI (max is about 30). The electronic controlled VGT turbos, like yours, will be similar if under like conditions, although much less noticeable with stock air intake. The condition is likely the computer adjusting the turbo performance under load. A sustained load, like ascending a grade, will allow the computer to normalize the entire system, and you may notice different noises than what you have become used to (even for short periods).
    1985 Blazer 6.2
    2001 GMC 2500HD D/A
    dmaxmaverick@thedieselpage.com

  5. #5
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    Mar 2010
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    NE Tennessee
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    Default Noise

    Thank you for the explanation. I feel better about it now.

  6. #6
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    Apr 2001
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    CA
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    Arrow

    It occurred to me that noise descriptions, like yours here, can be very subjective. Noises can't be heard through text. Anyway, another noise you may hear under load is the engine driven fan. Most often, it's described as a "roar", but could be a whine via the ears and description of some folks. Still, a normal condition.
    1985 Blazer 6.2
    2001 GMC 2500HD D/A
    dmaxmaverick@thedieselpage.com

  7. #7
    Join Date
    Mar 2010
    Location
    NE Tennessee
    Posts
    16

    Default Noise

    I think it is the turbocharger. I wish the manual would explain these things better. Thank you.

  8. #8
    Join Date
    Jan 2001
    Location
    New Hampshire - Live Free or Die
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    6,073

    Default

    I would call the noise from the turbo a whistle, or like a distant siren.
    The Constitution needs to be re-read, not re-written!

    If you can't handle Dr. Seuss, how will you handle real life?

    Current oil burners: MB GLK250 BlueTEC, John Deere X758
    New ride: MB GLS450 - most stately
    Gone but not forgotten: '87 F350 7.3, '93 C2500 6.5, '95 K2500 6.5, '06 K2500HD 6.6, '90 MB 350SDL, Kubota 7510

  9. #9

    Default

    Turbo whine comes from firewall - if you open the rear slider window and the whine is coming from behind you, thats probably a pinion or u-joint bearing. Check all fluid levels in drivetrain.
    2011 Chevrolet Tahoe 5.3L daily driver
    • Previous owner of two 1994 6.5L K3500s, '01, '02, and '05 6.6L K2500s, '04 C4500, '06 K3500 dually, '06 K3500 SRW, '09 K3500HD SRW, '05 Denali
    • Total GM diesel miles to date : ~950K

  10. #10
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    Mar 2010
    Location
    NE Tennessee
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    Default Location

    Hard to pinpoint the noise source location. Seemed like it was coming from the engine compartment.

  11. #11

    Default

    Turbo, if you only hear it during acceleration and/or towing. Normal! Its a GOOD noise...
    2011 Chevrolet Tahoe 5.3L daily driver
    • Previous owner of two 1994 6.5L K3500s, '01, '02, and '05 6.6L K2500s, '04 C4500, '06 K3500 dually, '06 K3500 SRW, '09 K3500HD SRW, '05 Denali
    • Total GM diesel miles to date : ~950K

  12. #12
    Join Date
    Jan 2009
    Posts
    116

    Default

    Got the same under the same conditions. High pitched whine right at the firewall. It changes with engine RPM and scared the BG's out of me. I thought maybe it was fan clutch slipping as the tranny was getting hot and I was going slow. Fan roar I know but this was much higher pitched. I asked around at the dealer and others and no one had a definite answer.
    2008 2500HD Ext. 4X4
    265/75R16
    Reese Signature 18k slider
    Montana 38.4 ft 5th wheel

  13. #13
    Join Date
    Dec 2010
    Location
    Felton, DE
    Posts
    35

    Default High Pitched Whine when cold

    I've only had the 'beast' for two weeks now and only driven it 4-5 times. This morning (as did the day I picked it up...35-45 degrees outside) there was a high pitched whine that mirrorred the engine RPM when the engine was cold. It only lasted for about 3 miles then went away.

    To me it sounded like an alternator bearing, but I read something about a belt pulleys wearing out prematurely.

    Any thoughts on what this can be. I'm still in my work clothes and may have to try to track down the noise Saturday morning.
    Jon
    04 Silverado 2500 HD Duramax (LB7) 173K Miles
    97 Passat TDI 200K+ Miles
    00 Passat 1.8 150K+ Miles
    97 Corvette 110K+ Miles

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