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Chevy Silverado and GMC Sierra Transmission Problems



  • kananskanans Posts: 1
    edited August 2011
    I have the same issues. My company finally bought me a new truck instead of letting me inherit the next oldest truck. They got me a 2011 GMC Sierra. I am a car guy, ex mechanic. It has 10K miles on it now. From day one, at stoplights I have had to look in the mirror weekly to see if I got rear ended, nope, its the **** tranny. And it always seems to hesitate excessively when letting of the gas and then hitting it. It also hesitates when I need to pull out onto a road from a dead stop. I lived with it because hey, I didn't pay for this truck my company did. I average about 100 miles a day between customers. But this morning I got a green left turn arrow so proceeded into the intersection. Halfway through I notice a typical zoned out driver to my right blew the light and I had no choice but to put it to the floor so the commuter wouldn't slam into me. Well... my high quality GM pickup decided that was a good time to exaggerate the transmission hesitation. When I put it to the floor there was a SOLID 3 COUNT before it decided what gear the slushbox tranny needed. It was annoying at first, but now its dangerous. I have never trusted american automatics, so sad that manuals are on their way out. My personal car is a manual and I will never buy an auto unless I have no choice. GM please fix this, it is a real issue! I was so excited that my boss sprung and spent the extra cash to get me a V8 4wd but sometimes I wish I had my 99 chevy silverado 2wd underpowered V6 company truck back. At least the tranny knew how to shift!!!
  • obyoneobyone Posts: 8,054
    sometimes I wish I had my 99 chevy silverado 2wd underpowered V6 company truck back. At least the tranny knew how to shift!!!

    So you're saying you would rather have the old 4L-60e vs. the new 6L-60e. The 4L-60e had it's share of problems including early torque converter lockup at around 39 mph. Perhaps a stall converter would help you out cause unless you're connected I wouldn't hold my breath on getting help on that 6L-60e.
  • chuck1chuck1 Posts: 1,405
    edited July 2011
    "I have never trusted american automatics, so sad that manuals are on their way out. My personal car is a manual and I will never buy an auto unless I have no choice."

    You will NEVER BE HAPPY with the 6 speed if your personal car is a manual.

    Next time your online, check out the complaints with the new transmission in the new Ford Focus, many complaints there too. In automobile manufacturer's quest to wring out every mile-per-gallon possible, they are making dual "dry clutch" automatic transmissions and doing all sort of exotic things you are probably not up on, unless you have been in a automotive classroom recently.

    The 6 speed in the GMC trucks is not a smooth power train, but if you do research on the web they are not trouble prone as some on this board would have you believe.
  • chuck1919chuck1919 Posts: 176
    edited July 2011
    Full descriptions of new or changed features

    New application:
    The Hydra-Matic 6L80 six-speed automatic transmission is the only transmission offered in the “New” Chevrolet Camaro SS when mated to the “L99” 6.2L V-8 VVT (L99) which is equipped with Variable Valve Timing ( VVT ), and Active Fuel Management ( AFM ). The 6L80 ( MYC ) is also a 2010 offering for the Chevrolet Corvette. Additionally the six-speed transmission is mated up with our strong family of Vortec engines in many of our world class GM trucks which include, Chevrolet Avalanche, Silverado, Suburban, Tahoe, GMC Sierra, Yukon, Yukon XL and Denali series, Cadillac Escalade, ESV, and EXT.

    Modular design for application flexibility:
    Because of the modular design of the Hydra-Matic 6L80 six-speed automatic transmission, there are different bell housings and different extensions that adapt the transmission to the front-mounted car and truck applications that can be configured with rear- and four-wheel-drive. The unique compound gearset in combination with a conventional simple gearset on the output carrier of the transmission allows both the durability necessary for the torque output of the V8 truck engines, as well as a flexible selection of gear ratios with a wide ratio spread.

    The Hydra-Matic 6L80 is six-speed automatic transmission for rear-drive cars, designed with modular flexibility and compatibility with advanced electronic controls. It was introduced for the 2006 Model Year Cadillac STS-V high-performance rear-drive sedan, and the XLR-V and Chevrolet Corvette two-seat sport coupes and convertibles. For 2007 model year, the Hydra-Matic 6L80 was added to the new Cadillac and GMC full-size SUVs and GMC Sierra Denali Pickup. The aluminum case for all these applications is identical, however, the bell housing for each application is unique because of the engine & driveline interfaces.

    All applications feature adaptive shift controls. Several additional features such as grade braking, Performance Algorithm Shifting, and Driver Shift Control are available on some of the applications. Performance Algorithm Shifting (PAS), which detects when the vehicles are being driven in a spirited fashion and remains in its current gear ratio even when the driver lifts a foot off the accelerator pedal. PAS monitors how assertively the driver is using engine output to determine at what engine speed to upshift or downshift. Driver Shift Control, available in the Corvette, STSs and XLRs allows the driver to shift the transmission like a clutchless manual gearbox. Electronic safeguards prevent over-revving should the wrong gear position be accidentally selected.

    A wide overall ratio spread of 6.04:1 allows a "steep" first gear, as well as very "tall" overdrive top gear for low-rpm highway cruising. Acceleration is maximized, as is fuel economy. Engine noise is also lower during cruising. Both fifth and sixth gears are "overdrive" gears, for example.

    Gear changes from second to sixth gears are accomplished with clutch-to-clutch control, where an oncoming clutch is engaged and an "offgoing" clutch is released in a precise manner to achieve the ratio change. The first-to-second upshift, however, is a freewheeling action, where the second gear clutch engages while the first gear one-way clutch spins freely. This allows a greater degree of smoothness at lower vehicle speeds. The clutch-to-clutch shifting and single freewheeler allows significant reductions in packaging requirements and, as a result, the new six-speed is nearly identical in size to the four-speed transmission it replaces.

    Advances in transmission control modules allow the modules to exist reliably inside the transmission, where temperatures remain fairly constant compared to a body-mounted module. The transmission and module are assembled together, so no additional steps are necessary during vehicle assembly.

    The 32-bit transmission control module (TCM) monitors transmission performance and compensates for normal wear in components such as clutch plates, so transmission performance remains consistent for the life of the transmission. The control module also "tests" the components of the transmission following assembly to optimize the interaction of the components. The module is compatible with future global applications.

    DEXRON VI premium fluid validated to improve durability and shift stability
    A new transmission fluid, DEXRON VI, was developed to have a more consistent viscosity profile; a more consistent shift performance in extreme conditions; and less degradation over time. Internal GM tests have demonstrated DEXRON VI delivers more than twice the durability and stability in friction tests compared to existing fluids. The DEXRON VI fluid was designed specifically and validated for the new family of GM six-speed automatic transmissions.

    While the basic aluminum housing for 6L80 transmissions can remain identical for a wide variety of applications, including front- and rear-mounting, car and truck applications, and rear- or four-wheel-drive applications, the case extensions and bell housings can be modified for nearly any longitudinal drivetrain vehicle. The modular concept of the new Hydra-Matic 6L80 six-speed automatic centers on the desire for common components and manufacturing tooling for four different size variants of the new 6-speed family. The main case uses three main components, and those components are the same for all variants of the transmission. For the first applications of the new transmission, the 6L80-E contains three gearsets, a conventional input planetary gearset with four pinion gears. There is one compound output gearset and one simple output gearset. The compound output gearset uses three sets of pinion gear pairs, with one set of pinions meshing with the sun gear and the other set with the ring gear. This arrangement allows for optimal ratio steps with a 6.04 overall ratio spread.

    There are two torque converter sizes, 258mm and 300mm. The 258mm applications use a twin-plate torque converter lockup clutch, while the 300mm applications use a single-plate torque converter lock-up clutch. Both types of clutches make use of GM's proprietary electronic controlled capacity clutch (ECCC) technology, which uses a small, regulated amount of slip to dampen out engine pulses. This creates a smoother running drivetrain, especially during shift events.

    Low maintenance:
    For severe use, DEXRON VI fluid changes are the only maintenance recommended. For normal use there is no fluid change scheduled.

    The Hydra-Matic 6L80 is produced in Ypsilanti, Michigan, Toledo, Ohio and Silao, MX

    Bottom line-we are all "feeling different things" because the transmission are using different methods of switching gears than we are used too. The car companies want to stop the energy waste in the transmissions. Not saying this is good or bad on how they behave. But it you own one, accept this technology or as I stat
  • lstriplstrip Posts: 42
    Your constant defense of this transmission is getting old.
    There is enough documentation to prove
    it is a flawed design.
    It is obvious that your job is to downplay
    the negative press.
    For those of us that are trying to get this issue
    resolved, we ask that you go cash your GM paycheck
    and move on.
  • obyoneobyone Posts: 8,054
    Who did the last rebuild as they usually come with a 12k warranty?
  • chuck1chuck1 Posts: 1,405
    There is enough documentation to prove
    it is a flawed design.

    The following were sales of the trucks in June-

    Silverado - 32,496
    Sierra -14,558

    Where are all the unhappy owners with the design flaw?

    Just asking?
  • Jeff Gordon Cheverolet
  • Chuck - I happen to be one of those non existent unhappy owners. Whether it's a flawed design or not, there is definitely something wrong with some of these transmissions and GM needs to take care of these problems under the drive train warranty. Instead we are being told by GM mechanics and service managers that what is going on with these trucks is normal. I would be happy to have GM buy back my truck, and maybe they can sell it to someone else who would like to have their transmission learn how they drive. When you spend close to $40,000 on a truck, the least it should be is reliable. It is sad when i have to be embarassed to have anyone ride in my brand new truck, because it runs like junk!
  • lstriplstrip Posts: 42
    Sales numbers have nothing to do with
    this problem. Many of us are previous
    or current owners of GM products.
    It was after purchase that most have realized
    the issues with this transmission.
    Again, enough with the GM propaganda.
  • obyoneobyone Posts: 8,054
    I would be happy to have GM buy back my truck, and maybe they can sell it to someone else who would like to have their transmission learn how they drive.

    Have you investigated what your state requires to qualify for it's lemon law? Have you filed complaints with the BBB online against your dealership AND GM? Consulted with a lemon law attorney? GM will not buyback anything unless they are forced to. Anything else is wishful thinking.
  • ceb66ceb66 Posts: 70

    You got it! 45 year old Owner of six (6) former GMs. Never a complaint.

    Then this thing. Very disappointing.

    Doesn't make sense. The complaints are identical; clunking/banging/rough ride during AFM operation etc.

    The response by GM is too similar: "operating as designed/intended, electronic transmission has to get used to your driving habits..." C'mon?

    The "happy owners" don't get it. We're not checking sites like this because we have nothing better to do!

    As said before, the "happy owners" need to go to the "happy owners" site and talk about "units" sold.

    If I could "undo" this whole thing, GM would have their "unit" back.

  • chuck1chuck1 Posts: 1,405
    "Clunking banging transmission 2010 Silverado" (or any variation thereof) turns up less than one page on a google search.
  • sorry it took me soooo long to find this form. i didnt know in 2007 they had the 6 speed!!! i though or was told 6 speeds came out in late 2009. anyway how do we start a class action law suit. 2008 gmc sierra slt that looks like a Denali 3 transmissions 5 reflash 2 rearend carriers 1 whole new rearend new ecm and tcm 10 or so splin lubes new splin more lube all the door lock motors replaced ac head unit and lashing from locking torq like there is no tommorow GM DEALERS THIS IS ALL NORMAL give me a brake
  • i did learn my service mgt but again as all have said GM says this is normal and what a coincidence my service mgt has a truck and has the same problem come on. the trick here is gm has told them what to say so after 5 years or 100,000 miles they are in the clear major recall is needed and to all you gm service people stop jerking us around
  • Today I made what I considered to be a great deal on a new 2011 Silverado 1500 Texas Edition with the 5.3L engine and 6 speed tranny, but I am going to have to pass on it now. No way I'm going to risk it after reading all these complaints. (I have a nice GM Card rebate I need to use, but I'm having a hard time finding a GM product in my price range that I want to buy.) Thanks for heads-up on tranny, all you unhappy owners! I'll keep looking for something else- maybe Traverse or Lacrosse, but I would have enjoyed a good truck more.
  • chuck1chuck1 Posts: 1,405
    Really curious how tx_architect signed up for Edmunds just to make this one post!

  • lstriplstrip Posts: 42
    Really curious why chuck1 continues to post
    Oh thats right, he's the gm employee
    trying make it seem like just a few disgruntled
    owners complaining.
    Not working chuuuck.
  • My transmission has a hard shift between 1st and 2nd gear, at about 15 to 20 mph, when you let off of the gas and then press the gas pedal again. I took it to the dealership and they said "it works normal". I just don't want any other problems to occur because of the hard shift. Why is it every time a dealer has to do warranty work they say it works fine. Also two days ago the whole dashboard went out, even the gear shift . I took it in this morning and they said the computer showed no problems. I have a 2010 silverado crew cab with the 5.7 and 20,000 miles. I just would like to know the actions needed to get my vehicle fixed, I don't want to have this problem and get cared thousands of dollars to get it fixed after the warranty is up.
  • I signed up to make my initial post because I am grateful to the many unhappy owners who shared their complaints with the online community and kept me from buying a potential lemon. If you are wondering why I never posted before, it's because I haven't bought a car since 2004. I proudly own a 2004 Buick LeSabre Custom and a 2000 Buick Regal, bought new after reading positive reviews on the internet. My last new car before that was a 1986 Camaro Z28, which I loved and drove for 14 1/2 years. I need to add a 3rd car because my son will need one for college, and I will give him the Regal. I research all my major purchases nowadays, but this is my first experience with the user comment section of Edmunds.
    By the way, I wanted to buy an Impala LT, but found the seats to be too hard, the interior too plain, and the rear middle headrest a visibility hazard. Now I will need to figure out if GM even makes a dependable, comfortable car that I fit in and I can afford- it's seems to be much harder than before.
  • chuck1chuck1 Posts: 1,405
    Did you go back to the beginning of this thread and count how many owners are having issues? To be fair we are talking about the redesigned Silverado/Sierra that came out in '07 with the six speed as an option with certain motors.

    I did, and I am not to count them again, but it's somewhere less than a dozen (a very vocal dozen people). Some, complain about a clunking (which does not happen all the time) but this does not affect the shifting whatsoever. And remember, there was about 50,000 units of the Silverado/Sierra sold in June. People would not be buying them thinking there were wide spread issues. I would find it hard to believe some of these 50,000 people didn't do some Internet searching beforehand and come across some of these posts, but saw the small number of complaints and bought anyway based on the outstanding value these trucks provide.

    So you changed you buying decision based on 12 people?

    Based on your post I assume your not hauling or towing.

    Good luck on whatever you decide.
  • obyoneobyone Posts: 8,054
    The 2010 Silverado does not come with a 5.7. If in fact you do have one, that could be part of the problem.
  • SORRY it is a 5.3, if you don't have any solutions don't answer.
  • obyoneobyone Posts: 8,054
    Ok now that we've got that cleared up. Let's move on. When you took the truck into the dealer did you describe the hard shift to a service advisor? Did you have a tech ride with you so that you could demonstrate the hard shift and have the tech acknowledge what you are describing as a hard shift?

    Your dealer has dozens of warranty issues to deal with everyday. The techs try not to spend too much time on warranty work as they are paid a commission on revenue generating service. To get them to work on issues you have to help them identify what you're trying to describe to the service advisor. If not, you will most likely get a "could not duplicate" on your work order or as in your case they found no codes and found everything working within specifications.
  • So the problem didn't occur when we took a test drive. I had the same problem with my 2005 Jeep Grand Cherokee and they had a recall on it, and it was fixed years ago. I just don't want to have over 100,000 miles (drive train warranty) or even 36,000 and the transmission blow up. I spent a lot of money on this truck and think it should have any problems like this. I have taken vehicles to the dealership for warranty work in the past and it is pulling teeth to get something fixed. I just want to make sure that this problem is fixed now or I guess I need to get ride of it and buy a different truck other than Chevy. Also the instrument panel went dead yesterday twice and even the shift points weren't showing. And of course , it was not doing that today. Should i just get rid of it now before it all get worse??? Thanks
  • Just got my 2011 Silverado back from the dealership repair shop for the third time.Same old story, they drove my truck for 55 miles and couldn't find or feel anything wrong. The funny thing is that I picked up my 14 year old daughter and her friend, and the first thing they say is" what's wrong with your truck, it feels like it's going to quit running, I thought you were getting it fixed."Amazing, a certified GM Mechanic can't feel it, but a 14 year old girl can. I guess I will have to deal with GM directly, and from the sounds of it, probably will need a lawyer. Good luck to me and those other so called few unhappy GM truck owners.
  • chuck1 didn't they only sell it in 2007 2008 2009 and some of 2010 with the L480 E trans and everybody who was buying waited till 2011 to get new 6 speed? cause when i got mine in 08 there was talk about new 6 speed, just like the 1500 diesel. i could be wrong but no 6 speed was offered down here. this is only one site go to look up 2008 gmc trans problem so to say 12 post more like 100's. and for the ones that dont post they could care less maybe a lease or given as a work truck cause fleet does make good deals with big bussiness so that 50,000 could be this

    lidarules1 you got big ones. I stoped taking my kids in the truck after the wife almost rearended a car cause the dam thing would not down shift
  • I am Having the same Issue with mine which is a 2001 Chevy 2500 HD it seems to only really do it when it warms up though, is that the same fore you as well?
  • chuck1chuck1 Posts: 1,405
    " this is only one site go to look up 2008 gmc trans problem so to say 12 post more like 100's"

    I have, I am a member of some of those sites. It's the same thing - very few complaints based on volume sold.
  • chuck1919chuck1919 Posts: 176
    How many miles on your 2500HD?
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