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Chevrolet TrailBlazer Maintenance and Repair

Talk about Trailblazer problems and share solutions here.

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  • I have a 2002 EXT trailblazer that has a chronic road vibration that starts at 40 MPH peaks at 60 MPH and exists through 75 MPH. My dealer has looked at my TB 6 times and has no clue. The dealer does recognize that a heavy vibration exists but won't change out parts just because. On my own I replaced the drive shaft, rotors, and tires. Still no change. The vehicle shutters starting at 40 on up. My smooth ride of new is no longer. The problem was a slow gradual problem that is worse each month. I read all the other post and still I get no satisfaction or solid idea. My trailblazer shutters when the tranny is placed in neutral at 65 MPH. I even shut off the motor at 65 and still feel it so Im sure it not motor or tranny related. Towing makes it worse.

    ANY IDEA'S !

  • burdawgburdawg Posts: 1,521
    What kind of wheels do you have? Factory alloys or aftermarket?
  • It sounds like you have a bad tire(s). The tires of today break belts and unless the mechanic puts the vehicle on a lift, cannot tell they are defective. Sometimes even then it takes pulling the tires off. Have all your tires looked at. My 2000 Prizm had the exact same issue. Vibration would start at around 50 and stop once I hit 70. It was my tires. Your tires might be covered under defective warranties.
  • Wacky,
    I have own a ' 03 TBlzer LTZ and it experienced a very similar problem. A vibration in the rear drive train around 55-65 mph, especially in cruise. It was particularly a noticeable when carrying a cargo load or when carrying 4 adults. When in cruise and accelerating up a long hill, it was really a problem. I called the local (large) Chevy dealer who claimed that they never heard of such a thing and were not helpful at all.. I called a small dealership out in the county and the SVC mgr said right off that he knew what the problem was and furthermore, there was a GM service bulliten on it. The fix was a new set of rear coil springs. I called the big deal back and they still claimed that never heard of the bulliten. Anyway it took care of the problem for me.
    Good luck,
  • alcanalcan Posts: 2,550
    Sounds like classic driveline vibration caused by excessive or mismatched u-joint angles. Ask the dealer, or better still a shop which specializes in driveline service or off-road modifications, to verify front and rear joint angles. Should be 1-3 degrees with no more than 1/2 degree difference, if my memory serves me. Changing rear springs changes rear ride height and therefore changes u-joint angles. This is assuming that the driveshaft has been inspected to verify no dents or runout, and has been removed to properly check the u-joints.
  • Everyone thanks.

    The bad tire idea is just that, a bad idea. Tires have been replaced with a high end Goodyear Fortura tire. Same exact problem no better. I replaced the drive shaft with a one made of steel, this increased the problem 10 fold. The original was out of round by .030 front to back. Not a HUGE deal. I placed the aluminum back into the vehicle because the vibration made it un-drivable. The spring theory could be it. I'm just theorizing how that could fix it. The ride high makes or has no effect on the vibration at all. The U-joint angle could be set wrong from vehicle assemble I suppose but all of this was a gradual problem that got worse.

    One thing I notice those is the front end is very loose. The struts rattle over every bump. Sounds like their falling off at times. Maybe a connection their. My dealer is playing dumb and does not want to dig any further. Nothing like spending huge money and not getting the ride that it had when new. Their is nothing like making a payment on a vehicle that is a lemon. I must say those that of all the SUV's I have owned, this TB is the most comfortable of all.

    Keep the idea's coming in. I appreciate it.

  • "The bad tire idea is just that, a bad idea."

    I should have read your post more closely, I apologize for suggesting something you have already done. The other posts seem to be hitting on the possible problem. My EXT runs fine, so I'd appreciate an update if you find the solution in case I have to deal with it in the future.
  • Hi. My 2002 TB LT started something really strange a few days ago. As the days pass, the "symptoms" are becoming more apparent in different areas. Under normal conditions the following things should happen:
    ***Keyless entry should lock/unlock one/all doors with horn/lights.
    ***Rear window wiper and fluid should work
    ***When key is removed from ignition, radio should still play for ten minutes, interior light should come on and windows should still roll up/down.

    NONE of these are working or ALL of them are working. It's intermittent and hard to figure out the problem. If the door unlocks with the keyless remote, all of the above mentioned will work correctly. However, when i turn the engine off and the radio turns off too, I can't use the keyless to lock the doors and arm the alarm. I called the dealer (out of warranty of course) they said $500 for a computer Switch assembly with labor. Does this sound like a correct diagnosis? Any ideas? What can I check for? is there a site that has a diagram or description of what the modules do or which computer controls what? I'm lost. please help. :(
  • I have just replaced the transmission for the 3rd time in as many years. Has anyone heard of this before? My husband is urging me to trade it, but I don't really want to. Can anyone give me some hope?
  • The A/C fan on my 2002 TB has begun to work only when it feels like it. The air coming from the vents is cold, with or without the fan (I turn off the recirculate switch and the outside air will "adequately" cool the cabin when the vehicle is in motion). If I hit the top of the dash board a few times, after driving a while, the fan will often start blowing (although it seems like it is blowing lower than the speed it may be set on).

    Any ideas? I'm tempted to take the dash apart and look-see but I'm afraid I won't find anything I can simply fix. Someone suggested to me that the relay switch (located under the glove box) may be bad... it almost sounds like a poor connection or short too...but what do I know. in Las Vegas...A/C is a big issue... suggestions are appreciated.
  • Welcome to the TB air conditioning woes club. We have an 02 EXT and about 6 months ago had problems identical to yours. Thankfully we have the GM extended warranty. Ultimately you are probably going to have to have a new version of the thermostatically controlled cooling fan installed on your TB to fix the problem. Our dealer hemmed and hawwed, acknowledged that GM was having this problem with a lot of TBs and no real solutions. :cry: Finally after we located some info on the problem in the Edmunds "Trailblazer, Envoy, Bravada" postings and showed them to the dealer they "found" a TSB on the problem. A new fan and some re-pprogramming seems to have resolved our A/C woes. Suggest you check out the above mentioned postings, do a search for Air Conditioning and take the info to your dealer to get your A/C back to normal. Good luck.
  • I am having this same problem with both the vibration and the loose front end. I have taken it to the dealer about the squeaking over every bump, but they didn't hear it of course. Now I am having another problem (more serious) with the engine shutting off. I am taking it to the dealer today and will let you know what they say about the vibration. If you find the problem please e-mail or post it.
  • i have the same problem with the a/c. i have 02 tb, few months after we bought it rear a/c does not work so took it to the dealer and got it fix a few months later the same thing happen then the tail lights was not working properly and i think they have to fix it 3 or 4 times then one of my tail light has water inside the taillight itself because it's been raining it goes on and on then this past month the computer is not working during the trip to busch garden and took it to the dealer andit was the computer head board that cost $580 and has to stay for 3 days in the shop because they have to special order it and of course this happen on the 37,000 miles and you know what that mean it not cover anymore and now i am having problem with the power window on the rear side so i told my husband we are going to get rid of it before we spend more money on it and will never buy another chevy no more
  • I have a 2002 TB with 37k miles and recently started having problems with the oil pressure. My gauge reads that I lose oil pressure after about 20 minutes of driving and only when I'm decelerating. Otherwise, for the first 20 minutes and when I'm not slowing down the gauge reads normal. It has plenty of oil.

    Has anybody had problems like this? Also, I've read a couple of places that Chevy extended parts of the warranty for TB's for 5/60k. Is this true? This seems like a pretty big problem for a TB with low mileage.

    Any help would be appreciated. Thanks.
  • gmfangmfan Posts: 188
    You would need to tell us what your oil pressure gauge in reading. I have an 02 TB with 75K miles and at idle when engine is warm, my oil pressure is very close to if not at 40. Each time I accelerate or race the engine, it will increase. If I run it hard, it is common to watch the pressure to rise to around 60. This has been the characteristic of mine since brand new. If yours is displaying a lower oil pressure (specifically at idle while engine is warm), then there could be a manifold leak that a new gasket will fix...not too expensive around $300 for parts and labor. Let us know what your pressure is displaying.

  • gmfan, really curious now as to what manifold leak affects oil pressure.
  • gmfangmfan Posts: 188
    I meant valve cover leak with worn seals/gaskets. Or, it could be an oil pump that is going bad, are you using 5W-30 or 10W-30 motor oil? If you are using the thinner oil, why not change the oil with the thicker one to see what happens before you take it in. What is your oil pressure reading at idle? If it is reading at or below 15, I would immediately change the oil. If that does not take care of it, then you would need to take it to mechanic since he has an oil gauge tool. How many miles are on your vehicle?
  • When i first start my car, my oil pressure is normal (right around 40) but after driving for around 20 minutes, when i decelerate or let it idle it will then drop to nearly 0. As soon as I hit the gas it jumps back to 40. I believe I'm using 10W-30 oil right now.'

    My car only has 37k miles on it. I took it to the dealership today, but would appreciate anymore feedback so I can ask the right questions after they diagnose.

    If it is a bad oil pump, would GM possibly help defray some of the costs (since it has such low miles and just left the 3/36k warranty period). If so, do i discuss with the dealer (not where i bought the car) or call GM?

  • My 98 blazer is loosing coolant approx. 1 gallon + a week. It doesn't smoke, it has no leaks any ideas what it might be. My guess is the head gasket? :confuse:
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