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Chevy Tahoe



  • aacukaacuk Posts: 16
    I have a 1999 2 door Tahoe, 5.7 vortec LT.

    Question :- If I change my back axle ratio do I also have to change anything on the front end?

    Thanks in advance Roy.
  • sebring95sebring95 Posts: 3,238
    Question :- If I change my back axle ratio do I also have to change anything on the front end?

    Absolutely! Unless you never plan to lock it in 4x4 again!
  • aacukaacuk Posts: 16
    Thank you for the reply, this could be the start of sorting out my problem.
    When my Tahoe left the factory it was fitted with options 'G80 positraction, limited slip - GT4 3.73 Ratio', at some time in its life prior to leaving the USA the complete rear axle has been changed for a conventional axle of unknown ratio. (There are NO IDENTIFICATION MARKINGS on the axle now fitted. 1. How do I determine what the ratio is? 2. If it is not 3.73 ratio could this be the cause of a loud banging/grating sound (like gear teeth jumping) when I select 4x4?
    It is OK in 2 wheel drive. 3. What would be the easiest/cheapest to change, front or rear ratios? :cry:
  • rmarutrmarut Posts: 8
    I recently purchased a used 2002 Yukon (Wanted a Tahoe but got this Yukon instead) I had it for a few months and one day I noticed bubbles in the paint along the folded seam on the rear hatch... this caused me to look at all the seams on the doors (at the bottom) and the hood... They all had the same rust issues. I didn't look as closely as I should have when I purchased it... as it was a "Certified GM Used Vehicle..." to make a long story short... I had to fight a little to get the local GM body shop to fix it... or should I say post pone the end result... It has only been 2 months... and the rust issue is back on the hatch... I started looking at other Tahoe's and Yukons to make a trade to get rid of this rusty vehicle... only to find that everyone I looked at... was in the same condition... I looked at 3 2003's and 1 2002. I even checked my friends 2003 Chevy truck... and his seams in his door are doing the same thing and he does not drive his truck in the winter and only has about 15,000 on it... he keeps it more for show than anything. Just wondering if anyone else is having this problem. Thanks.
  • piercemanpierceman Posts: 47
    Aren't our hatches aluminium?
  • jlflemmonsjlflemmons Posts: 2,242
    I don't know where you are geographically, but I don't think I have ever seen rust on a GM truck or SUV here in central Texas. And there are a lot of them around!
  • rmarutrmarut Posts: 8
    These vehicles have all been looked in northern OH, PA and NY. I realize we are in the "rust belt" but on a vehicle that is only 2 years old... and not driven very much... to have rust in the seams of the doors... it just isn't what one would expect... don't get me wrong... I love the Yukon and Tahoes... best looking vehicle on the road today.. I like everything about it... except the fact that it has rust issues. My other GM products never had these issues even when they were 7-10 years old. Thanks.
  • aa555zzaa555zz Posts: 55
    My 2002 Tahoe does the same thing and the oil is at the correct level. However, mine does not leak enough fluid to dip onto the floor. The front axle assembly does not use transmission fluid. It uses gear oil. If your front axle oil has been changed, make sure they used the correct oil. Transmission fluid is red in color. Gear oil has a distinct smell.
  • bradstahoebradstahoe Posts: 1
    I may be one of the millions with this complaint...but my dealer keeps reassuring me there is nothing wrong with my 01 tahoe LT 4x4 transmission. I have a very frequent hard shift from first to second gear-regardless of the terrain (coupled with the "clink" noise). When the tranny is cold, it even lunges a little when trying to shift. At times the transfer case seems to have a vibrating noise coming from it. The dealer has checked it all out, and said nothing is loose. Anybody with this same "complaint" about hard shifting and what can I do?
  • sebring95sebring95 Posts: 3,238
    Wow, yeah the symptoms you describe could happen due to having different axle ratios on the front & back. The easiest fix IMHO would be to swap back a facory rear axle (locking or not doesn't matter, just go 3.73) since the front hasn't been changed.

    There's a way to figure out the ratio, but you'd have to find the specs. You should be able to match rpms & speed to a specific rear ratio. I don't know of the top of my head how to do this or where to find the factory specs. Sometimes they're listed in service manuals.
  • dynastydynasty Posts: 2
    I bought a 2004 Tahoe 4.8 L last November. My wife uses it primarily in the city. We only have about 4k miles on it but the gas mileage really sucks. I have been reading about this on the boards but I think my mileage is so bad that something must be wrong. I am only getting about 11.5-12.5 MPG. Has anyone else seen their mileage this bad? We do use it on the highway about 20% of the time and the mileage remains about 12mpg. What can be the cause of this? What are some of you experiencing as far as miles goes? Please give me some feedback. I love the vehicle but the mileage really should be this bad should it?
    Fred :confuse:
  • sanandtonsanandton Posts: 342
    I have had 2 Tahoes 2003 LT, and 2004 Z-71. My LT was 2wd and it had a problem of a delayed shift from 1rst to 2nd gears. It would begin to try to shift, but be slow about making the entire shift, then suddenly a distinct bump would occur as it finally made the shift. It felt like someone had tapped my bumper from behind. Never got it fixed, so traded it in when it got 36k miles for my 2004 Z-71.

    The Z-71 is 4wd and it has always had what I call "slop" in the drivetrain. It feels like my old 76 Camaro when the Universal joints would wear out. It shifts harshley especially when not under load, such as letting off of the accelerator in the parking lots. Frequently there is a distinct Metallic "Clank" with the shift as well. My dealer installed some extra lubrication yoke which really did not fix it. At the same time they reassured me it is a common issue. Almost common enough to reassure you you have a GM truck just by having the problem.
  • aacukaacuk Posts: 16
    Thanks for the info Alan, not many American axles knocking about here in the UK so I will order a new 3.73 ring & pinion from my local American parts dealer & swap it for the one that is in there. ;)
  • jay_24jay_24 Posts: 536
    mpg could be that bad. depends on your driving style and conditions. If you have lots of stop-go conditions and seldom hold a steady pace it could be 11mpg. We get about 12mpg (80% city) in the winter. Come summer and warmer temps it comes up to about 15 or so. Straight highway its quite good at 18 to 19mpg.
    Check your tire pressure. I tend to run a pound or two above recomended pressures. being just a pound low can affect mpg.

  • arriearrie Posts: 312
    I think you just must have 4 sensors in the vehicle all reading high enough pressure to keep warning off. I don't think there is a way to disable it if one tire with sensor goes flat other than fixing the tire.

    Perhaps this is good so it makes you go and fix the tire sooner?!?

  • arriearrie Posts: 312

    I have a 2004 Tahoe but with 5.3 l engine. This might make a difference but perhaps not.

    I wrote about this in my reply to dubois. You can find it on page 260 in this forum.

    I can now tell about my gas mileage that it definitely is at least 18.5 mpg driving on interstate highway on 70 mph speed limit area at speed that most everyone seems to drive. Before I got it fixed (as explained in my reply to dubois) my gas mileage was down at 13 - 15 mpg at these speeds.

    If I drive on a highway at 60 mph speed my gas mileage goes up to 21 - 23 mpg.

    I am absolutely sure that the engine in my Tahoe (like in all same model Tahoes) has a design problem with the crank shaft position sensor which causes this sensor to read wrong as it heat up with hot engine oil splashing on it.

    There are a couple easy things you can do. One is to go and have good people in an Auto Zone store to read codes from your vehicle's computer. It probably does not have any but have it done anyway.

    After codes are read have them to read I/M monitors. They should all say READY (other than the NOT APPLICABLE ones). I had a problem with EVAP SYSTEM not being ready before I changed my crankshaft position sensor. If any of the I/M monitors is showing NOT READY there is something wrong and usually it means that fuel consumption goes up as the computer in the vehicle goes in a pre-programmed control mode where it does not use signals from different sensors like oxygen sensors for fine tuning fuel injection in the engine.

    But, as I learned in with my Tahoe, check your engine oil level. If it shows full or above full mark drop it down a little bit. The dip stick in my vehicle has an area cross-hatched that is 1.5 inches wide. The manual says oil level in any point inside this area is fine so I dropped mine from higher than full mark down to half way and this simple procedure improved my gas mileage by about 2 mpg! Hard to believe but true.

    Read my reply to dubois and see what you think.

  • aa555zzaa555zz Posts: 55
    This web page will explain how to determine your axle ratio.
  • brian77711brian77711 Posts: 1
    I have the same problem in a 99 Suburban. Two dealers said it was the yoke and inserting grease was the only solution--it sounds like a major engineering flaw and GM will not recall! They also said a new yoke would not fix it. Do you know anything else?
  • aacukaacuk Posts: 16
    Thanks a million James, I found this site really helpful.
  • philryanphilryan Posts: 1
    I have had what I believe is a similar problem for the past 35,000 miles and the service mechanic gave me a copy of a service bulletin that stated that this was a normal situation on "some" vehicles. Other than the occasional clunk during low speed shifts, I've had not trouble in almost 59,000 miles.
  • sanandtonsanandton Posts: 342
    Yeah. The service dept at both of my local GM dealers have the attitude that all of them do that and that it will not shorten the functional life of the drive train. Oh well. Hope they are right.
  • aacukaacuk Posts: 16
    I have exactly the same clunk when pulling away after stopping.
    What type of grease did you use to solve this problem (will high melting point grease do it?) :sick:
  • dardson1dardson1 Posts: 696
    My 04 LS 5.3 2wd consistently gets 15+ mpg around town and 19-20 HWY if I drive the limit w/cruise and 17-18 if I drive 80-90. I've had a slew of SUV's and landed on the Tahoe for their great combination of decent gas milage and generous size. Never owned the smaller V8 but it stands to reason it ought to do at least as well as the 5.3. Keep those tires inflated. Even one low tire will drop my milage quite a bit. Maybe your wife is driving like a 16yr. old boy on 4 tires with 20lbs pressure. . .lol. Good luck
  • dardson1dardson1 Posts: 696
    I've been slow about getting my 04 in for the steering solution. I traded my 02 for the 04 thinking they certainly would have the issue addressed in 2 years. Hum? Same old problem in the new one. I keep hearing the replacement part was backordered 'til the crack of doom. At 8k miles my 04 was rattling like crazy in a slow turn. Took it in on Thursday, last week, without much hope of anything but a lube. Told them to lube it if necessary or do the fix if possible. They had the part in stock. . .2 of them according to the service guy! Got it back Friday before noon. Drives like a new car (which is should). Hope the fix is real. Can't put my finger on it. . .I've owned a slew of cars and SUV's. . .but I love my Tahoe(s) the best. GM knows how to make a big truck.
  • jake8jake8 Posts: 8
    what are the differences in brands? Hellwig, Addco, Eibach, G-max and Hotchkiss? the prices 200-650$ for front and rear. Are there really big differences in there sway bars?
  • dynastydynasty Posts: 2
    Thanks for your replies everyone. I plan on taking it in to the dealer and having them look at the on board computer this week. I just can't believe the mileage could be this bad. You guys are confirming my suspicions. Keep up the replies though as I would like to know what I should be getting as far as mileage.
    I do use the recycled air almost all the time. I was reading in the owners manual that this causes the A/C compressor to turn on. I still don't think this would drop the mileage this much though. Also, Has anyone ever noticed that when they are reading thru the owners manual that it states that the on board computer will tell you when you need to change the oil? This suprised me. But it does state this and says you may be able to go a year without an oil change. It's funny, just this past weekend I recieved a coupon flyer from the Chevy dealer with a coupon for an oil change that they recommend at every 3000 miles or 3 months (std I know) But now I am wondering if their mechanics even know about this (I mean who really digs into the nitty gritty on the owners manual). There is quite a routine to just reset the message on the tahoe to turn off the "time for an oil change" message. I wonder if they reset this every time they do a oil change service. Any thought on these topics? Like I said I would like to see some more responses for your real world mileage on the Tahoe's. Thanks for your responses up till now. You too Arrie!
  • steverstever Posts: 52,571
    I go by the manual myself and do the minimum, and I drive them forever. Others don't agree with me though:

    Maintenance Madness II: Dealer vs. Manufacturer Maintenance Schedules

    Steve, Host
  • jonnyb1jonnyb1 Posts: 32
    I think if you search the web for LS1Tech you will find some crazy folks dropping turbos and superchargers on their Tahoes.......mostly Silverados but same engine. ;)

    I think they are getting 50-70 hp and obviously the MPG gets pounded and you run the risk of grenading your engine. I read one case where some kid put in some lumpy cam and it demolished the engine.......
  • arriearrie Posts: 312
    Just a short version of my long story:

    -Changing crank shaft position sensor improved my gas mileage from 14 mpg to 17 mpg. It also fixed the EVAP SYSTEM NOT READY problem. I only had EVAP SYSTEM READY for about two weeks when the Tahoe was new and what time it gave me 17 mpg. Now since the crankshaft position sensor change it has stayed at READY state.

    -When changing the crankshaft position sensor I learned that the sensor gets really hot as it is mounted in the side of the oil pan. Sensor also was oily. This gave me an idea of lowering the oil level in the engine and when I went to check the level it was 1/4 inches higher than the high mark on dip stick. At next oil change I asked the dealer leave it at half way mark and this improved my gas mileage to about 18.5 mpg. The gas mileage here is with 75 mph on flat interstate highway with no wind and no drafting. When I drive 60 mph my gas mileage is at about 23 mpg.

    -With the above changes last week on one of my trips I drove 444 miles with 23 gallons of fuel. 2/3 of this driving was on interstate highway and rest through small towns on highway with 55 - 65 mph limit. When my Tahoe was 'sick' I could only drive about 340 miles with 24 gallons of fuel.

    -Yesterday I removed the heat shields from spark plug boots. The shields leak some of the spark in engine ground and removing them saves a better spark to the plug. This fixed a rough idle that I have been experiencing a lot and also seems like made the engine run much smoother. My gas mileage seem to have improved some also but I have not been on highway yet to see. I would not be surprised if my mpg now is 19+ on interstate.

    -When removing heat shields I noticed that especially one of the wires was loose on the plug. It didn't matter how hard I pressed it in. It just didn't snap on the plug. I changed that one as I still had the other set (had changed them twice already) and when inspecting the connector I could clearly see how it had been arching between the connector and plug. I will next find a set of high performance spark plug wires to make sure they are not causing any problems. GM uses some really cheap design wires where the connector gets loose on plug really easily.

  • dardson1dardson1 Posts: 696
    I have a trip computer on my LS. One of the buttons on the steering wheels cycles thru a list of things on a window under the speedometer. At 3k miles it tells me I'm about half way to the need for an oil change. Consumer Report did an interesting test using NYC taxi cabs not too long ago. Their conclusion. . .3k oil changes are unnecessary even under the constant stop and go miles in a Big Apple hack. I let my first change run to 4800 miles at which point the computer suggested I had about 30% oil life left.
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