Results 1 to 16 of 16

Thread: LBZ / Allison - Cracking, snapping, popping, ticking sound???

  1. #1
    Join Date
    Sep 2001
    Location
    Michigan
    Posts
    119

    Angry LBZ / Allison - Cracking, snapping, popping, ticking sound???

    The truck is a 2006 2500HD with LBZ Duramax and 6-speed Allison, <19,000 miles. The drivetrain has been making what I would describe as a chorus of LOUD cracking, snapping, popping and ticking sounds during cold and warm starts when the ambient temperature is about 65*F and higher. It doesn't make the noise every cold / warm start but it does it on a fairly regular basis. The noise is almost a certainty during hot ambient temperature starts (80's & hotter) when the engine is cool or warm.

    As the engine comes up to temperature, the noise seems to dissipate and eventually go away, most of the time. There have been several instances though that the noise took about 10 miles to dissipate - it's obvious and loud enough that people's heads turn at stop lights.

    There really doesn't seem to be any rhyme or reason to the noise other than it is there at idle, both in gear and in park. The noise is still there off-idle but you reach a point where engine noise overtakes the noise as you are pedaling the accelerator. The noise is coming somewhere from the powertrain or something that is connected to it - the noise seems to emanate most from the underside of the truck and the wheel wells. I have had the hood up a couple times when it was making the noise and it doesn't seem to be a top end noise - it is much more obvious through the wheel wells and truck's underside.

    I can not say there a correlation to engine speed - sometimes the engine will be idling and you hear a random "tick" thrown in about once every second. Other times you hear a "tick, tick, tick" at a much more frequent interval that seems rythmic to engine speed. Other times, it's a louder cracking / popping sound - almost like a hot exhaust - but much louder and much crisper. Shut the engine off, no more noise.

    The only thing I have ever heard make a noise like this in a vehicle is a cracked flex plate, but the truck has done this almost since day 1. By the time I get the truck to the dealer when it is making the noise, the engine has warmed up enough where it's quiet. Finally, on an unrelated service call, a Technician heard "a noise" but the noise dissipated before they could find the source - then they couldn't duplicate it.

    Any ideas what this noise could be? It has not proven to be a functional issue yet, but the fact that the noise is there on such a regular and frequent basis is keeping me from having my peace of mind.

    Thanks!

  2. #2
    Join Date
    Feb 2000
    Location
    Maplesville, AL - Home Base
    Posts
    536

    Default

    Mine does a similar thing at start up. I her a crackingpopping metallic noise mostly from the drivers side. After a few minutes it goes away and never is noticeable other than right at the side of the truck. While in the cab with the door closed you can't hear it at all. It seems to come from under the driver's seat.
    Ed
    Ed
    KM4STL

    '06 Sierra LBZ 4x4 Crew SB, Titan 52 gallon fuel tank, TTT/Schefenacker Mirrors
    '98 Suburban, 245,000 - sold 7-4-06

  3. #3
    Join Date
    Feb 2000
    Location
    Montana
    Posts
    11,382

    Default

    Take the serpentine belt off to see whether the sound is being produced by any of the engine driven accessories. The water pump is gear driven, so other than the alternator not alternating, you should be fine for the few minutes it might take to eliminate the accessories.

    If it does it while sitting still, it's likely not the transmission, transfer case or drivelines. The flexplate and TC might be, but...

    Jim

  4. #4
    Join Date
    Mar 2007
    Location
    Pacific Northwest
    Posts
    740

    Thumbs up

    If this is the same noise that most all DMAX trucks have, it sounds to me like what you are hearing can also be described as a sound like a loose spark plug wire creating a "SNAP" sound. This is a known condition that has been around since the 2001 LB7's were out. The noise sounds like a mechanical typewriter. The last explanation of this from GM TAC was that it is caused by the thrust of the camshaft (end play). Another time it was thought to be cavatation in the oil. There used to be a bulletin for this. Basically a letter stating all is good and no engine damage is being done nor will there be any long term effects. I tried to locate the bulletin, but I am having no luck. I will post it here if I find it.
    1998 Chevy k-2500 454 147,000 miles and climbing!

    1993 Pontiac G/A Big Block 3.3 Liter 140,000 miles and still going too!

  5. #5
    Join Date
    Apr 2001
    Location
    CA
    Posts
    13,573

    Arrow

    ^

    Bulletin No.: 02-06-01-022F (last updated 11-30-06)

    If the noise sounds like a mechanical typewriter, that's probably it, and it's normal. It'll decrease with time and miles.
    1985 Blazer 6.2
    2001 GMC 2500HD D/A
    dmaxmaverick@thedieselpage.com

  6. #6
    Join Date
    Feb 2000
    Location
    Montana
    Posts
    11,382

    Default

    GM decreased the engine oil pressure in the LLY and LBZ engines below that produced by the LB7. The odd snapping (produced by the earlier LB7) didn't seem to be an issue with the newer engines - at least people stopped talking about it.

    To me, the snapping sound produced by the LB7 was more like a loose flat washer intermittently rattling/ticking inside the driver's side aluminum intercooler tube. I felt then (and still do) that the sound was due to new oil gassing-off and creating gas bubbles that were compressed/popped in the engine's main/rod bearings. I always heard the sound right after an oil change and for about the next couple hundred miles - then not again till the oil was changed.

    Jim

  7. #7
    Join Date
    Apr 2007
    Location
    Alberta, Canada
    Posts
    311

    Default

    i always thought it was metal parts expanding as it warmed up........

    similar to the sound you hear from ducts in the house when the furnace kicks on maybe......

    just my thought but i'm not sure
    2011 VW Jetta TDI, pretty well loaded without leather.
    2006 GMC Sierra D-max, 4x4, 4 door, bumper, winch, Espar heater, and the HID lights are a nice touch too.....
    1986 GMC 3500, 454 on propane, 4 speed, 4x4, crew cab dually......the welding truck
    1984 Toyota 4x4 pickup, 4.3 V6, 700R4, Toyota t-case.......transforming into 4x4 cage buggy

  8. #8
    Join Date
    Jan 2007
    Posts
    115

    Default

    Not sure what you are talking about the snap, pop, cracling sound, but I sure do know what you are talking about that ticking sound. There is a bulleting out for it, but GM says do not fix and it is normal. Mine is ticking too, sounds like some one using a mechanical type writer with one finger. Sounds worse on the drivers side wheel housing, when it's warm outside and the truck hasn't reached op temperature. However, it shouldn't effect anything, besides making noise.
    07 Chevrolet Classic, CC, regular box, Duramax Diesel, Magnaflow dual exhaust and Superchips tuned.

  9. #9
    Join Date
    Feb 2000
    Location
    Maplesville, AL - Home Base
    Posts
    536

    Default

    As I said earlier, mine does this too, but only while it is coming up to operating temp. Then it is quiet. Did anyone actually say what it is? If so, I guess I missed it. Ed
    Ed
    KM4STL

    '06 Sierra LBZ 4x4 Crew SB, Titan 52 gallon fuel tank, TTT/Schefenacker Mirrors
    '98 Suburban, 245,000 - sold 7-4-06

  10. #10
    Join Date
    Mar 2000
    Location
    bayville, new jersey, USA
    Posts
    280

    Default

    what kinda oil ya using ? i ve been using 15w40.....mobile delav mostly,

    slight noise when oil is new but after few hundred miles, ticking noise is gone,

    my 02 dmax was another story....lots of ticking till the oil was diluted with diesel when the injectors went bad......

    i notice on the lbz, the oil pressure is much less than the 02.......when approaching 5 k on oil it s way down on the pressure gauge at idle.......
    '12 gmc sierra 2500 dmax slt carbon black.
    '12 s350 diesel mb
    '10 mazda 6i, for sale
    '77 450sl benz, in family since new, sold, still in jersey thou
    '91 350sdl benz, 3.5l diesel, 28 mpg
    '90 560sel benz

  11. #11
    Join Date
    Nov 2000
    Location
    foxboro,ma.
    Posts
    908

    Default

    I have had 3 duramax trucks , every one of them has had the oil cavitation cracking/poping sound if they have fairly new oil in them. I use Rotella 15-40 , the issue seams ot go away as the oil ages some . my 2001 was the loudest and had the highest oil pressure. 27 min hot and 60+ at road speed hot. the LLY truck had slightly less oil pressure but still did it and my LBZ has less of a issue but it still does it if the oil has less then 2000~3000 miles on it.
    93 c-2500 6.5td,96 6.5td x cab,01 GMC lb7 Xcab ,2004 lly crew cab ,2006 lbz crew cab,honda CBR1100xx,2003 polaris prox 700 , 2001 31' holiday rambler 10K lbs house on wheels!

  12. #12
    Join Date
    Jan 2007
    Posts
    115

    Default

    I don't see or hear any difference if the oil is new or 7000km on it. Ticks the same to me. It is only doing that during warm up, never during Op temp.
    07 Chevrolet Classic, CC, regular box, Duramax Diesel, Magnaflow dual exhaust and Superchips tuned.

  13. #13
    NutNbutGMC Guest

    Default

    Quote Originally Posted by hapaschold View Post
    ...
    my 02 dmax was another story....lots of ticking till the oil was diluted with diesel when the injectors went bad.........
    LMAO... Been there.

  14. #14

    Question Cracking, snapping, popping, ticking sound???

    Any further ideas on this noise?? Any one know for sure what it is?
    My 2004 is doing it now at 105,000 miles. Sometimes it gets so loud that I think the truck is about to explode. Comes and goes, sometimes happens for 5 minutes sometimes 30 minutes then I can go a week without hearing it. Several times I have had to pull over and shut down for awhile in the hopes that I can get home.
    Going in for service on Wednesday. See what they say.

  15. #15
    Join Date
    Jan 2007
    Location
    Orange County CALIFORNIA
    Posts
    9

    Default Snap Crackle Pop

    I had a 91 Ford F150 a long time ago that made the exact same sounds that you described. It drove me nuts! Finally one day when my drive shaft fell off when I put it in reverse (the front end of the shaft next to the transmission) I saw that the needle bearings inside of the universal joints were TOASTED at both ends of the driveshaft. I took it to a drive shaft specialty shop and had both "U" joints replaced with "U" joints that had zerk fittings so they could be occasionally lubricated. END OF STRANGE SOUNDS END OF STORY. This might be your problem or NOT .. Something to ponder. I have a 07 GMC LBZ now with 20K miles and have not heard any of these type of sounds yet but if I do I am lookin at the U joints first.

  16. #16
    Join Date
    Oct 2008
    Posts
    27

    Default snapping, crackling noise

    I was getting a similiar noise on my 06' but only at Gear changes ya know from park to drive and reverse and park again and also when i would pull away from a stop. I took it to the dealer and they found that indeed i had bad u-joints so they replaced the entire driveshaft and i have not had any noise since
    DIESEL5 93' Chevy 2500 4x4 6.5 turbo stock and 06' 2500 4x4 crew cab, duramax with edge juice +attitude , 5 inch exhaust turbo back and K&N intake. "What a runner"

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •