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Vibration / Noise GMC truck 1999



  • lintlint Posts: 2
    Has anyone had any trouble with a door rattling? I have already had it in the shop once for this, and now it is rattling again. I have a '99 sierra 4x4
  • squanksquank Posts: 4
    If your "rattle" is a sort of random tapping sound that seems to come from inside the door or cab - but low and behind the driver/passenger - check underneath the cab, just behind the door. There are some cable ties which span the joint where the cab sits on the frame - may be a ground or something - these were loose on mine and the noise was generated when they swung back and forth behind the bolt head. Noise stopped after tightening them a bit. Takes a large wrench and some hernck, but they will tighten. There is one on each side of the cab. Have seen this complaint from others as well.
  • squanksquank Posts: 4
    I have been told by the service mgr at the dealer on 8/17/99 that GMC should be coming out with a TSB fix for the 99 Sierra drivetrain vibration at the end of August. It apparently involves the replacement of the rear springs with stiffer ones that raise the rear-end a bit and change the angle between the tail of the trans. and the differential (as someone here had mentioned as a possibility before). Hopefully this will solve the problem w/o creating new ones.
  • obeardenobearden Posts: 34
    Have a look at topic # 654. Might need to go back 15 to 20 posts, but lots of info available
  • gl3gl3 Posts: 31
    I have a 99 excab silverado, 4x4, I have also
    experienced the windshield noise ( I have a Lund
    bugshield ) I also have had wind noise from the
    3rd door 1/4 window, dealer replaced the latch
    but still have noise. Currently trying to solve
    "clunk" from rearend when traveling over small
    bumps. Dealer said was spare tire,the tailgate,
    now replacing rear springs. Anyone else have this?
    Annoying as hell after spending that much money.
    Dealor has also installed "anti clunk" seal.
  • obeardenobearden Posts: 34
    When you hear the "clunk" sound, is it while you are re-accelerating? Is it above or below 1500 RPM and do you feel a forward jolt at the same time? If so, you probably need to have the EPROM re-flashed. The reflash addresses this and several other issues. The "clunk" is probably the torque converter locking after momentary heavy acceleration. The re-flash prevents converter lock-up below 1500 RPM. Mine hasn't done it since the reflash. More info to come....
  • obeardenobearden Posts: 34
    Go to this GM site
    and enter your VIN Number. Be
    patient, it sometimes takes a while for the site to
    respond. You will get the details on all the flash
    upgrades from the past. Each upgrade includes all
    the preceeding changes. As you will see, there are
    several issues addressed in addition to the one you
    mentioned. Print the resulting page and take it to
    the dealer.

    Good Luck, it worked for me.
  • obeardenobearden Posts: 34
    I don't know why the link above doesn't work. It worked fine for me a week or two ago. It won't even work from my favorites. All I can say is wait a day or two and try it again.
  • gl3gl3 Posts: 31
    Actually it is more of a "clank", it happens
    even when "coasting" so I don't think it is the
    converter. It is a metal to metal sound under
    the rear end area. Almost sounds like a loose
    caliper but I have applied the brakes and it still
    occurs. I will suggest the two sided tape for
    the windshield to my dealer, is there any adjust-
    ment on the 1/4 window? Not much faith in my
    dealer service dept. Site still will not open
    will keep trying....thanks for info, obearden.
  • quadrunner500quadrunner500 Posts: 2,728
    Sounds like gear backlash in the rear end to me. To me, I'd rather hear that, if it was occasional, than worry about not having enough backlash.
  • quadrunner500quadrunner500 Posts: 2,728
    Link is dead, for now at least.
  • obeardenobearden Posts: 34
    Does sound like gear backlash. I was hearing some of this before the reflash, but not now. Be aware that on the new trucks, when you release the accelerator the converter does not unlock as in the past, so when you put your foot back down there is no give in the drive train. The flash keeps the converter unlocked below 1500.

    gl3--when you say coasting, do you mean you just hear the sound when you are coasting along before you re-accelerate?
  • obeardenobearden Posts: 34
    About your quarter window, this might help temporarily. Run you air conditioner only in the recirculate position. When you put it in the other setting, lots of outside air is introduced and this pressurizes the cab and could cause a lot more leakage and noise. But note that if you go about two click past the foot vent setting toward defrost setting, the system will overide and force the introduction of outside air.
  • gl3gl3 Posts: 31
    The noise occurs when going over a bump. It does
    not matter if I am in the gas or letting off.It
    can be just a small pothole or speedbump.Dealer
    says it is the springs slapping together. they
    said they tied a creeper to the bumper and pulled
    a tech around he lot. Who knows? And I have noticed that the AC settings affect the noise.
    Just seems like a pain ya know? Thanks
  • mfreemanmfreeman Posts: 37
    Sounds like a pretty stupid thing to do, but at least you know they are welling to risk life and limb to fix your problem.

    ... so I wonder what sounds the creeper made when it went over the bump? :)
  • gl3gl3 Posts: 31
    Well lets put it this way, the first time I had
    the oil changed they left the fill cap off, and
    whoever works on it must not know how to wash his
    hands as it is a black truck and always comes back
    with greasy handprints on it. So I am not real
    confident in their abilities. It goes in Wed for
    the new rear springs, cross your fingers.
  • obeardenobearden Posts: 34
    Keep us posted...
    And by the way. I don't buy the creeper story for a second, they were pulling your leg if they told you that.
  • gl3gl3 Posts: 31
    Well, picked up truck from dealership, and
    to my far. Keep your
    fingers crossed. And it looks like they actually
    replaced the springs. My service invoice this time
    stated that they "hooked ears up to rear of truck
    to find noise" I don't believe the creeper story
    either but they actually wrote that on the last
    work order. If this indeed does fix this, I think
    I can live with the 1/4 window and W/S noise. I
    think they might need to work on the T/Converter
    though as the other day in the rain it was clunk-
    ing like hell in between shifts. I also heard
    something this morning for the first time...lifter
    chatter when I first started it..anyone else have
    that? It is the 5.3 Does it ever end? Thanks
  • gl3gl3 Posts: 31
    I forgot to advise that the GM website is back up
  • marcmarc Posts: 21
    I have the same "clank" when going over speed bumps......
    Also, sometimes when I am stopped and shift from D to R I hear a loud clank in the drive train, like bad U joints.
  • gl3gl3 Posts: 31
    Look back at some of the other comments,
    is your truck xcab 4x4? The first time I had the
    clank in the drive train the dealer installed
    what they called an anticlunk seal (spacers in the
    rearend) this did not help. I am going to see how
    long the noise going over bumps stops with the
    new leaf springs. Not much faith in my service dept. Have your dealer look at the springs in yours, mine is 2nd set the dealer has changed, the
    first was on a 2wd. Then have them look at your
    gear backlash and torque converter, Hope this helps.
  • jdbuffjdbuff Posts: 5
    Are these vibration and noise problems only on the 4x4's?
  • obeardenobearden Posts: 34
    My valves have started chattering in the morning the first time I start the truck too. It started about two months ago after an oil change. I have changed the oil again since and it did not go away. The Chevy service manager told me that he has heard there was a number of oil filters (PF59) that had a bad check valve. I did by those last two oil filters at the same time. The chatter shouldn't cause any problem but it is rather annoying. Next oil change I'll advise if it goes away. It didn't chatter the first 28K miles.
  • gl3gl3 Posts: 31
    No I think they are on all of them, I have a buddy
    with a 2wd Xcab and he gets the windshield noise
    and several dash squeaks. He has not mentioned
    any drivetrain noises or vibrations yet but I
    have seen 2wd complaints here. Alot of new model
    bugs in these, havn't heard from anyone local with
    a 2000 to compare, all my buddies have 99's
  • I have a 99 2wd extended cab GMC. I'll share some of the problems and solutions. I had a vibration from day 1 that felt like out of balance tires. The dealer checked the lateral run out on the standard chrome wheels and found they were out. Three sets later (none met spec.)they are putting aluminum on. My qtr glass was replaced due to wind noise and my front spring spacers were replaced for squeaks. I hope that's all that occurs!
  • If you haven't already done so, you need to read this topic from the beginning (click "see all responses" above the first message displayed) then go to topics 547 and 654 and do the same there. I know it's a lot of reading, but believe me it's worth the trouble. And don't give up, there is hope. Problems aside, don't you love the truck?
  • Had some of the same noises described above on my '99 SL reg. cab long box 4x4. The solutions/causes my dealer and I have arrived at were done before I learned of this site.
    1) "clanking" in rear end: Overload spring hitting on other springs. See a solution described above.
    2) "Slapping" or "vibrating" noise in windshield:
    Is actually caused by the two thin rubber "strips"
    that cover the hood hinges. They are designed to be lose, and are generally quiet on trucks without bug deflectors. The bug deflector causes turbulence, which causes the rubber strips to flap back and forth at highway speeds. If this is your problem, you can actually see them flapping back and forth if you look closely while driving. Haven't come up with a good fix yet, and neither has GM as far as I know.
    3) "Buzzing" vibration from under the cab, usually present when accelerating at slow speeds: Exhaust heat shield under passenger seat vibrates. Service tech gave it a slight "bend", which totally resolved the problem on mine this far.
    4) Cab "bounce"; cab bounces up and down at highway speeds, especially on rough roads (gets really irritating after 100 miles or so): Tech. re-torqued rubber mount bolts, which really helped. The bounce I'm talking about is really obvious when you put a topper on; you can see the cab bouncing up and down when looking out the rear window at the topper. Need to keep these tight.
    Love my Sierra; fourth new GM truck now, won't be the last! Hope this helps someone. . .
  • Have to disagree about number 2, above. I removed the piece you are talking about altogether. Still had the flapping sound, until I taped down the rubber windshield seals with some black vinyl tape. Then I put the hinge covers back on and still no flapping, after the tape.
  • gl3gl3 Posts: 31
    I Have to agree, I too thought the "flapping" noise was the two strips on the hinges
    but have determined that it is the mouldings on
    the sides of the glass. I had my rear springs
    changed and the "clank" seems to have vanished. I
    don't know if it is me or not but the driveline
    clunk has become more frequent/louder after the
    spring change. Will have dealer try the Reflash on
    the converter to see if that helps. Lifter chatter
    has also vanished with recent oil change. My truck
    has 9000 miles on it. This is not my first new GM
    vehicle with new model problems. Had a 94 S10 4x4,
    95 Monte, 98 Blazer and now this. They all had the
    first year bugs but none as frustrating as this.
    Although I blame alot of my problems with my
    service department. Not much faith in them only adds to it. Will keep you advised on the drive-
    line noises.
  • Guess Quadrunner is one step ahead of me on the flapping. Thanks for saving me lots of trouble. Don't suppose GM will volunteer new leaf springs for all of us for the clank problem; glad to hear g13's is fixed, for now anyway. No clunks in my driveline (yet), and lifters are quiet (@ 9,000 miles). My automatic has a pretty loud "whine" when driving after my truck has been idling for a while in park on a hot day, however...
This discussion has been closed.