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Buick Rainier, Chevy TrailBlazer, GMC Envoy



  • You said:

    "Mine has the locking diff and doe not do it."

    I'm not suggesting that all vehicles with a locking differential will have this problem. Mine never did until about 3 months ago (after about 24K miles).

    You said:

    "It behaves just like a normal open diff until there is enough speed difference (about 200 rpm) between the two rear wheels to engage the locking mechanism."

    Right, but clearly, the thing is a mechanical device that needs to react to slippage in some way to lock up. There must be some sort of clutch type mechanism in there and I am suggesting that might have something to do with it.

    You said:
    "and if you are going over 20 mph it won't engage anyway. ":

    Right, but what does that have to do with a "stutter/clunk" that occurs while stopped?
  • pepper50pepper50 Posts: 195
    ylab wrote:
    anybody who's had the obnoxious clacking/ticking that sounds like a bad lifter should definitely try changing oil! I've had the noise since the dealer performed my first complimentary oil change and switching to 10W30 Mobil1 only made matters worse. Switched to 5W30 semi-synthetic and the noise has all but subsided within about a week of the change. (Apparently these engines HATE 10W30 oil even in the heat of summer....I'm thinking the dealer used 10W30 and not 5W30 on my first change).

    For my first oil change on my '02 Envoy, I noticed on the receipt that the dealer used 10W30 engine oil, so I asked about it, and he said that's what GM recommends the dealers use in all the Envoys in this area (North Texas.) I called 2-3 other dealers around here and was told the same thing. I don't know why they don't use the 5W30 like the oil cap states. I have a feeling it's because it's cheaper for them to buy 10W30 in bulk. So that's what the dealer has been putting in for subsequent oil changes, too. Maybe it's because of the southern climate here.
  • tblazedtblazed Posts: 945
    "It behaves just like a normal open diff until there is enough speed difference (about 200 rpm) between the two rear wheels to engage the locking mechanism."

    'Right, but clearly, the thing is a mechanical device that needs to react to slippage in some way to lock up. There must be some sort of clutch type mechanism in there and I am suggesting that might have something to do with it.'

    That mechanical device in the locking mechanism works from the >200 rpm difference in axle speeds to engage. Otherwise it is not engaged.

    You said:
    "and if you are going over 20 mph it won't engage anyway. ":

    'Right, but what does that have to do with a "stutter/clunk" that occurs while stopped?'

    Several times I have read it described as happening after coasting down to a stop from highway speed, or certainly from a >20 mph speed, and then getting the stutter-clunk. It would not be engaged from 1) highway or >20 mph speeds and 2)not be engaged unless the rear wheels were spinning 200 rpm or more differential speed, like one stopped, and the other spinning. Even if you locked the diff starting off from a stop, as soon as you get over 20 mph it will disengage.

    Just don't see how anything in a locking differential could store up enough energy to cause a stutter-clunk to be felt through the drive train and vehicle after a stop.
  • tblazedtblazed Posts: 945
    I use 10W-30 Quaker State and no problem. Above 0°F the owners manual says 10W-30 is OK. Did go back to 5W-30 for the winter though. 5W-30 will flow a little more easily cold, in the winter months.

    The main difference between the two is the viscosity when cold. When cold the 5W-30 will flow like a cold 5 weight oil, the 10W-30 like a cold 10 weight oil, and when hot, both like hot 30 weight oil.

    I noticed when I put in 10W-30 the cold engine noise was slightly reduced. So I use 10W-30 for my spring and summer oil changes, 5W-30 for the winter change. Same brand.
  • I suppose there are lots of variations of this theme, but IMHO there is nothing about it that should be considered "normal". Therefore, the "normal functions of the locking differential have nothing to do with the possibility that abnormal behavior from this device could be the source of the "stutter/clunk". I'm still interested in whether those who experience the problem also have locking differential.

    If people who do not have locking differential also have this "disease" then I will shut up about it possibly being the cause.
  • ficussficuss Posts: 541
    the same clunk heard and felt when you go from reverse to drive too quickly? Sometimes when I go from reverse to drive, it seems like the tranny shifts to second gear instead of first. When I accelerate, it starts off slowly then drops into first. The clunk it makes sounds like a drive train lag or something similar. The only time my TB has shuddered is when it was running very warm or near hot and the RPM's suddenly dropped to nearly zero and back up to 600 rpm. Recently, if I make a very sharp turn while parking, the engine will surge to the point where if my foot isn't on the break, I would probably jump the curb or into traffic. Does this sound anything like the shudder or clunk being described?

    BTW, is CLUNK even a word?

  • tidestertidester Posts: 10,059
    BTW, is CLUNK even a word?

    Yes. As a noun: A heavy dull sound (as made by impact of heavy objects)

    And, as a verb: Make or move along with a sound as of a horse's hooves striking the ground

    tidester, host
  • ylabylab Posts: 46
    My '02 doesn't have the locking differential and it exhibits the shudder/clunk occasionally. (Its an SLT with only a radio upgrade, no other no auto-locking Diff).

    Other than the shudder and some very minor valvetrain noise, which I've noticed in every overhead cam engine I've owned, no real complaints and very happy after nearly two years of ownership. Admittedly, I've massaged the vehicle a bit with CAI, JetChip and K&N Filter as well as a Denali grill, bug shield, weatherflectors, rear step hitch, mud flaps & rear wing.

    Anybody have experience with side tubes? Will they block the debris which the flaps miss or do I need to go with running boards? (Those black tubes look so much nicer on a white truck).

  • gam2gam2 Posts: 316

    No one seems to be mentioning the driveshaft yoke
    binding. As you stop, the rearend raises up and the yoke slides in and out. If it's binding, it probably slips the other direction under acceleration. It may just do it at a rest. Seems to me this is a common problem with pickup trucks.

  • Here's a question where I think the answer is rather intuitive, but want to ask anyway.
    Checking tire pressure on a spare vs checking pressure as the tire supports the truck. I would expect that a spare with 30# of air will gauge higher once mounted on the truck.
    Sort of like a balloon that gets squeezed. The pressure rises in another section and forces the ballon to extend.
  • took the 04 tb.for an rpm test,sticker says 3.73 2000 rpm in a level stretch of highway.speed was 65 mph.70 mph.2200 rpm.doesn't have the pulling power of the 02 i had,dont know what the problem could will find out or they will see me every other day.
  • kpp14kpp14 Posts: 62
    BTW, is CLUNK even a word?

    "Yes. As a noun: A heavy dull sound (as made by impact of heavy objects)"

    Tidester, you can be the keeper of the "New Sounds of GM" dictionary. Heres a new one we can put beside clunk. What should we call the sound your forehead makes rapidly tooting the horn after trying to describe the clunk problem to the dealer?
  • tidestertidester Posts: 10,059
    Would that be "slapdash?" ;-)

    tidester, host
  • I'm telling ya.. I am not a mechanic here, but my previous posting (13305) describes a fairly identical issue that was had on the 1999 - 2000 Jeep Grand Cherokee Limiteds.

    The posting references the slip yokes and I pretty much can guarantee that if the triplets have a slip yoke on them (to which I am sure that they do), this is the problem at hand! My 1999 Jeep Grand Cherokee Limited V-8 did the EXACT same thing as what we are experiencing. Mine in addition to a multitude of other JGC owners had experienced the same issues at hand.

    I haven't checked, but if this forum holds archives dating back to 1999, you can search the JGC forum for "Slip Yoke" and you will find the exact same problem as what we are describing..

    Just my two cents..


  • Tidester Host,

    Here's a suggestion for you to which I would like to gainer support from the group.

    Since there has been numerous issues about this forum becoming a playground for complaints, I propose the following:

    * Similar to the Honda Accord forum (and many others), I suggest that you FREEZE this topic of discussion and create two new ones! You could possibly create the following:

    1) 2002+ Chevy Trailblazer, GMC Envoy, Oldsmobile Bravada Problems (maybe include Buick Ranier, Isuzu Ascendor)

    2) 2002+ Chevrolet Trailblazer, GMC Envoy, Oldsmobile Bravada (maybe include Isuzu Ascendor and Buick Ranier)

    I honestly believe that this will help to keep the topics of discussion more focused to everyone's liking so that if they are 100% problem free with their vehicle, they can simply focus on posting messages to the "rants and raves" side of the forum (and vice-versa for those who have experienced "perpetual woes.")?

    In my opinion, I think that this is a very "active" forum and that's wonderful. Heck.. we are already nearing 14 THOUSAND postings people!!. However, there needs to be some sort of separation to help keep the topics more "focused" and to help keep the general audience happy. For example, I've been considering the new Honda Accord Coupe as a second car and found it QUITE pleasant to venture over to that particular forum and spend time reading the good and the bad... more so, educating myself in an unbiased way! Perhaps the "happy" forum can focus on more pleasant items such as: modifications, upgrades, accolades, "how to's (i.e. changing a light bulb)," etc. The "problems" forum can continue working collaboratively/effectively as we all do so well to help resolve/get answers to the problems at hand?

    Just food for thought... All those who agree TYPE EYE! :-)



    OH.. and let's not forget.. to keep things clean and searchable, delete those discussion threads that were created and contain less than 10 postings!!
  • ylab - thanks for the info.

    Iexplore/Gam2 -

    Slip yoke explanation seems to fit pretty well, but in my case I can pull up to a light and while I am sitting there, I feel this very light thump effect. Further, it sometimes repeats maybe two or three more times if I just sit there. The repititions even seem to be regularly spaced apart. These effects were what made me think something might be going on in the rear axle. It seems to me that friction release in the yoke would happen just once and it would be all over. But again, in my case, the effects are very mild. Many people probably wouldn't notice it.
  • tidestertidester Posts: 10,059
    How about keeping this one and creating a "Trailblazer, Envoy, Bravada Problems and Solutions Board" or somesuch? That would result in less confusion for people who participate here and would be easier to redirect people to the problems & solutions area.

    All in favor indicate with AYE and opposed with NAY! I thought I just heard Iexplore volunteer to keep count? :-)

    tidester, host
  • tblazedtblazed Posts: 945
    Why add another? There are already 23 titles including (edited) "Strange noise behind dash", "Transmission Problems", "Vibration 40-65 mph", "02 Trailblazer AWD problem", "Air conditioning problems", "Any battery problems after vehicle sits?", and "Air Noise" among others. No one goes to those topics. Look at the numbers of postings to each topic and see for yourself which one gets the most response. Some are read only now, likely due to lack of response.
  • tblazedtblazed Posts: 945
    RE message 13326, I had asked if the stutter-clunk is happening with 2WD, 4WD, or both, and will add locking or not locking diff to the question. Haven't seen any answers to the first part yet.

    Does anyone with this problem notice if the RPM is briefly dropping below the normal 600 when this happens?

    BTW speaking of words, "studder" is not a valid word, "stutter" is. As per anyway. "Clunk" is also valid word.
  • I own an 02 Envoy, with about 36K on the odometer...I recently noticed a "rubbing" noise apparently comming from the steering column at low, parking lot speeds. The dealer applied some type of lubricant to the steering column, claiming this would stop the problem....needless to say, the noise is still there...has anyone else had this problem? If so, what was the solution..thanks
  • steverstever Posts: 52,572
    Organization is a bit of a problem sometimes. We also have a Chevrolet Trailblazer Owners Club to muddy up the waters with.

    But most makes/models have a general board and a problems/solutions board. They grow in size, but the Discussion Search function makes it easy enough to find specific problem threads.

    Anyone interesed in the new version of DOD? "On a 15-minute drive, the TrailBlazer V-8 switched between four and eight cylinders more than 40 times without hesitation." USA Today

    Steve, Host
  • '03 Envoy, 4WD, locking diff, 3.73 gears.

    RPMS do NOT fluctuate when stutter occurs.
  • lurker01lurker01 Posts: 103
    I posted this a while back, but will again to add my $0.02.

    Clunk felt from undercarriage when stopped at intersection.
    Steps to reproduce: Truck must be cold. Start truck and drive short distance (<.25 miles) to a stop sign or intersection. Wait at intersection for ~1 min. You will feel a clunk or series of clunks from the lower rear of the truck. Feels like the car behind you didn&#146;t stop in time and tapped your bumper! Could be some sort of binding problem in the rear differential or other mechanical connection. After driving a few minuets and stopping again, the problem does not reoccur. However, the next time the truck is cold, the same thing will happen. Could it be a lubrication issue in some part that occurs after truck sits awhile?

    The service tech said: Normal Behavior.

    I have given up on this on and just live with it. I'm out of warrentee now anyway, so I can't go complain about every little thing anymore. Barring a recall fix, I don't see this going away.
  • boat10boat10 Posts: 59
    took delivery this past Saturday of my wife's new "BABY". Here's one for you.....Ordered on Saturday, October 25th, build date was November 3rd, shipped on November 5th, dealer received vehicle on November 12th, and paper work done Saturday November 15th. Friend purchased 2002 Trailblazer (I had leased) for his wife....Everybody HAPPY !!!!

    I'll have to say the 2004 drives a lot different than the 2002..stiffer sway bars, etc. Got 4WD, Silverstone with medium gray interior (LOOKS GOOD!), black wall tires, Bright Alum. wheels, leather, sun roof, DIC, running boards, 3.73 rear end, locking diff. ALL the GOODIES.
  • I agree with tblazed's comments about the number of forums, however that's why I am proposing that we go through and "archive (or make READ ONLY)" those triplet forums which have been deemed inactive and in turn create either two new ones as mentioned in my previous posting (one to include "Problems and Solutions" and another to include general information "Rants and Raves, How To's Etc."). For the most part, out of all the triplet discussion threads, people tend to realize that this thread is the "alpha" thread and switch over to it. If you don't believe that this is working, check out the Honda Accord threads.. They have several that are very active (Honda Accord, Honda Accord: Prices Paid & Buying Experinces, Honda Accord: Problems & Solutions) and each thread stays very focused to the discussion thread's subject. Most importantly, it's very easy to read and the conversations seem to flow a little better in these types of threads.

    Obviously, if a previous thread only has 4 or 5 postings and seems to be inactive, ARCHIVE it and steer discussion to the new threads. I think that this will help to clear the waters for those searching for active threads. OR.. as Tidester mentioned, keep this one going and start a new thread for "problems and solutions."

    BUT.. IMOP I somehow feel that it would be better to just archive this thread (along with others) and create two new ones. This will allow us to start fresh so that new comers can clearly choose a thread to surf without getting a "skewed" vision that the triplets are nothing but trouble.

    Just my two cents!



    ALL IN FAVOR.. TYPE: EYE! And yes I will keep count! :-)
  • ficussficuss Posts: 541
    I believe my G.M. mechanics are pretty smart. But, if I go in and tell them my car is stuttering or studdering, should I be surprised if they can't duplicate the problem? Now if I tell him the car has a shudder or that the car shudders at a certain speed, he may have a better chance of duplicating the problem. I think we should be as specific and accurate as possible when describing a problem.
     On the topic of possible additional forums, lets keep what we have now. If you have something to say, say it here. That way, we can all read the good, the bad, and the indifferent. I don't mind reading about mud flaps and lift kits even though I have no interest in either.
  • Exactly how my 02 SLT behaves (24K miles)and -
    Exactly what the tech told me: Normal Behavior

    re: 13348 of 13354 STEERING "rubbing noise?" by tripicchio

    Yep, I've noticed this too and the tech reported doing the same.'s still there. Feels, like you said, a "rubbing" or resistance in the steering column.
  • ficussficuss Posts: 541
    Infiniti G35 has several forums to comment on. I have found that the people who have something they want you to read will post it on both the generic G35 and on the more specific G35 problems and solutions board. This only wastes time when reading the comments. Besides, where would you post a question about mud flaps, on the generic or the problems and solutions board?

  • I guess I'm a NAY too. If you create a separate forum for problems, you'll get less solutions to problems there. A lot of times people who read this forum come across a problem and offer a possible solution, when they wouldn't normally browse a forum that is meant only for problems and solutions.
         Most folks have no problem offering a solution to a post if they're already there browsing that forum, but you can't expect people to go out of their way. I don't see myself ever waking up and thinking "Gee, I'm going to go out and solve some random people's triplet problems today."
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