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Chevy Silverado and GMC Sierra Transmission Problems



  • Has any one here in the forum thought about or tried to put true duals exhaust on a 6.0L to see if it helped in the performance and fuel mileage. I cannot believe that with all the technologies we have and a 2012 GMC 6.0L 6 speed transmission will only get 14MPG. Thats on a good day along with the no power issue. I am waiting to see what GM is going to do.

    As far as I am concern they can buy it back.
  • lchaney33lchaney33 Posts: 2
    I have a 2012 1500 with the 6.2 and the 6 speed transmission and have had nothing but problems since I picked up the truck.

    I feel that not only are the issues aggravating but also quite dangerous. I have found that I can not change lanes and expect the truck to accelerate without a HUGE amount of lag time.
  • What did you do about the Cat converters?
  • Just bought that same model truck. Transmission already playing games and the truck doesn't even have 1500 miles on it.
  • sounds about right. Mine right off the bat was surging on take off. Now when you hit third gear at a some what normal speed then try to accelerate it sound like it is struggling badly. Bogging
  • galvezfjgalvezfj Posts: 12
    Take it back to the dealer and complain. I took my truck in and had a ride along from the transmission tech. He's the one that said "Yes the truck is not shifting properly". Then i got a call from 866-790-5600 ext 11040 his name is Houston. He's a customer support rep that help me get my transmission replaced in my Truck. Hope this helps you. I went through the original and a rebuilt tranny before i hit 5k on the truck.
  • This is where I have seemed to get responses from GM getting them to act on warranty.

    Back in '02 no long after I bought my Silverado, it wasn't the transmission yet. It was the lifter tap. I actually had a Regional GM Representative make the trip to the dealership and assess my truck's issue.

    So go register your car and be heard.">link title
  • gmcustsvcgmcustsvc Posts: 4,003
    Thank you for taking the time to share your experience with GM Customer Service. :-) I am happy to hear you are satisfied after working with us. Please feel free to contact me with any questions comments or concerns.
    GM Customer Service
  • Is there a posted TSB (Technical Service Bulletin) on issues with the 2011 and 2012 6spd transmissions?
  • There is a service bulletin, my service manager printed and gave it to me. They are all aware of the problem but refuse to fix it. Apparently GM had to increase the average gas mileage of all trucks so they made the 6 speed and have it shift prematurely to lower engine speed and increase the mileage. Keep complaining to your dealer and then start sending certified letters to the CEO of GM
  • i have the same problem with my 09 sierra 5.3. im driving come to a stop then thump 4 seconds then thump and another 4 seconds then another thump then nothing. trying to see how many more ppl have this problem and if you have any info on this problem i would like some feedback.
  • chuck1chuck1 Posts: 1,405
    "There is a service bulletin, my service manager printed and gave it to me."

    AND what does it say?
  • I have the same issues with my 2012 GMC Yukon. I was told it's supposed to shift that way to increase fuel efficiency. I have my truck in the shop right now, this is the final straw. If they don't get it to drive properly I will have no other choice than to get a "Lemon Lawyer" I think GM should recall all of these trucks and replace the 6 speed with the old reliable 4 about a class action suit!
  • I would be interested in the lawsuit.
    my truck is almost 2 years old and its been doing this crap since the day I bought it new.
    it been in the shop more times then I can remember and told the same 2 stories. " its supposed to make noise and shift hard, its designed that way" OR " what noise? what hard shift?"
    my last trip was to a new dealership that admits there is a problem but will not put it in writing.
  • Has anyone registered their vehicle with GM on line and gone around the dealership? I've mentioned this before... This system works.
  • Hello, please elaborate on house you "went around" the dealership.
  • chuck1chuck1 Posts: 1,405
    El Hoppy-

    We have all heard numerous times how unhappy you are. Buy a Ford F150, RAM, or Tundra and move on.....
  • rayt2rayt2 Posts: 1,208
    The old reliable 4 spd auto is no better. My tranny went at 62k, 5 years ago :sick: . 2000 3/4 ton (7200gvw) Silverado 5.3 auto w/overdrive. My trans shop said unless you bought the heavy duty trans option all you were getting was the same tranny found in a Camaro. He rebuilt it with stronger torque converter and upgraded the brain to a Corvette module to quicken the shift. $1800 out of pocket. 95k so far on odo.
    Would I buy another GM product........NO ! and I tell that to anyone I meet on the street when they talk about buying one. Besides they have gotten pretty ugly in design to boot. Is Dodge or Ford any better? don't know their design dept has more going for it then GM's bland look, but that will be my next choice when I am ready to buy new again.

    Ray T
  • Bought my truck used from a Dealer in Arizona. I live in PA. What a mistake that was but thats another story. I bought a 2010 silverado 1500 with the 6.2L 6 speed 49,000 miles. The first trip I took as soon as I got out of my driveway the Tranny slipped and the engine just reved and went nowhere. As long as you babied it it would run just fine. So I take it to the Dealer they flushed the transmission thinking it was there for service and called me and said its all done everything is working perfectly. I said a flush fixed the slip? what slip? he replied. So they did tests and talked to a GM tech and decided to put a new valve body in it. I told them I smelt the clutch burning and it wasnt the valve body but GM knows best. So it didnt work and they tore the tranny apart and found a crack in the sleeve that holds the discs releaving pressure, fixed parts and on my way I went 2 weeks later. Now it lags when shifting from a dead stop to second gear and any time it has to shift down a gear going up hills or passing somebody. Took it back to the Dealer and they had it another 2 days just to tell me theres no codes coming up and we dont know what to do, my best GM tech says to put a programmer in it to see if that helps the tranny being confused because I have 35" tires. I said thats all good and fine but 35" tires arent gonna make my tranny temp go to 223 degrees when going up hills is it? He said no thats high temp but we are at a loss. I asked him does the 15 brand new vehicles you have on the lot with the Rocky Ridge package with 6" lift with 35" tires do this? no reply just we dont know.
  • Timid Temper doesn't your model have the 65e and 3.73 rear end?
    I maybe able to shed a little light for you.
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