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My own 8 speed problems & resolution


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My 2015 Denali did the same.  Hard shift and loud clunk shifting 2-1.  It would actually make the truck jump forward when it did.  Made for a couple interesting moments pulling in my driveway and in stop/go traffic.  The 1-2 shift was also hard but not as bad.  It was looked at several times, flashed the torque converter, normally said it "needed to learn".  After 20k the 2-1 shift was very bad and I traded it in.  My current 17 has a hard 2-1 shift with a loud clunk but it doesn't jerk forward.  The 1-2 shift often puts you forward in the seat belt, there is a complete lost of power for a solid second.  It gets worse with cool temps 60-50 degrees.  I haven't had the service center look at it yet.  It has less than 6k on it.  I'm going to wait and hope it gets better or worse.

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My 2017 GMC sierra 1500 6.2/ 8 speed with 4k miles just had TSB done on relearn of C3 return spring, i took it in because of the clunky noise on downshifts when coming to a stop. At first i thought it was fixed only to discover it wasn't, still clunky. It seems to downshift normally half the time and clunky the other half UNDER THE SAME EXACT DRIVING CONDITIONS. Also took in for rough idle, they adjusted the motor mounts then replaced them, no fix either, giving the truck some more time then I'm trading it in and never buying a GM truck again, what a damn joke this is for the amount i paid for this truck. Also forgot to mention they had my truck 14 days, i got lucky and they gave me a little Buick car for loaner, talked with others who had to endure longer times without getting a loaner. i hope eventually a class action lawsuit against GM is created for this transmission mess and the way they are handling it.

Edited by jtjohnston
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  • 2 weeks later...

Hello all! I joined this forum just for this problem. I had seen all the "Chevy shake" threads where there was no foreseeable reason as to why the trucks shake. My Sierra is a 16' premium plus with 5.3 and the 8 speed. It has always had an occasional "clunk", which doesn't bother me. But at about 14,500 miles I noticed the steering wheel would get an on/off vibration, at various times. Always when accelerating or cruising. Well yesterday I finally caught the rpm gauge bouncing and it matches the shaking of the steering wheel (which can also be felt in the seat). It feels like when you go off the pavement and run over the the grooves meant to gain your attention. So,  It appears I'm in the same boat with everyone else.

This is my 1st GMC truck and I love it, it drives and handles great, especially for a 4x4. Truck goes in this Friday for a check to see why it has a vibration. Hopefully GM finds a permanent fix. I was truly hoping to be done swapping vehicles as I want to drive this one until the wheels fall off, not shaken off.

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I really don't understand how GM gets away with selling these trucks with such problems that we all have. You would think that the buying public would hear about the transmission problems by word of mouth but they don't and keep on buying them like I did. I did not check the reviews on a new GMC truck before buying, I wish I had.  But now that I have it I am expecting GM to correct the problem but it seems that they want to use the excuse that the transmission has to learn my driving style, which I think is totally a cop out for not knowing how to fix the problem. You might think I am a little ticked of about this and you are correct. My name does not indicate that I can just get JUS1MO of these expensive trucks when I wish.

Edited by JUS1MO
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I'm in the same boat with you.
16 Sierra 4x4 all the goodies.
Going to try a different dealer, Never again will I purchase another GMC Truck, but I must say it is the nicest looking truck out of all of them.4e37a3d347b5ef7d21472df95493d2e5.jpg

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I'm in the same boat with you.
16 Sierra 4x4 all the goodies.
Going to try a different dealer, Never again will I purchase another GMC Truck, but I must say it is the nicest looking truck out of all of them.4e37a3d347b5ef7d21472df95493d2e5.jpg

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Best looking trucks on the road imho. I can't say I won't purchase another because they all have their own demons but this will damage the trust I have in the brand. I'm wondering if it's with the bigger cabbed trucks. I thought there was only the short door and bigger door trucks but the loaner I got when they had to replace my sunroof was full size doors but the cab was significantly smaller. Although it was a 2017 Silverado instead of a Sierra.

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Best looking trucks on the road imho. I can't say I won't purchase another because they all have their own demons but this will damage the trust I have in the brand. I'm wondering if it's with the bigger cabbed trucks. I thought there was only the short door and bigger door trucks but the loaner I got when they had to replace my sunroof was full size doors but the cab was significantly smaller. Although it was a 2017 Silverado instead of a Sierra.

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Silverado and Sierra is almost the same truck I think.
I needed 4 full size doors, sometime I have to take my aunt to appointments, and she pushin 360lbs.

So the trk is very handy.

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Silverado and Sierra is almost the same truck I think.
I needed 4 full size doors, sometime I have to take my aunt to appointments, and she pushin 360lbs.

So the trk is very handy.

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In the Silverado we were given I could touch my kids in the back seat (it had big doors and not the minis) although in mine I couldn't come close to touching. Yes, I love the huge cab space.

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Hello all! I joined this forum just for this problem. I had seen all the "Chevy shake" threads where there was no foreseeable reason as to why the trucks shake. My Sierra is a 16' premium plus with 5.3 and the 8 speed. It has always had an occasional "clunk", which doesn't bother me. But at about 14,500 miles I noticed the steering wheel would get an on/off vibration, at various times. Always when accelerating or cruising. Well yesterday I finally caught the rpm gauge bouncing and it matches the shaking of the steering wheel (which can also be felt in the seat). It feels like when you go off the pavement and run over the the grooves meant to gain your attention. So,  It appears I'm in the same boat with everyone else.
This is my 1st GMC truck and I love it, it drives and handles great, especially for a 4x4. Truck goes in this Friday for a check to see why it has a vibration. Hopefully GM finds a permanent fix. I was truly hoping to be done swapping vehicles as I want to drive this one until the wheels fall off, not shaken off.
Part 2. Truck went in to dealership, I don't think they even looked at it tbh but it goes in at some point this week to have the torque converter flushed 3x, supposed to be a 5 or 6 hour deal. As we talked he mentioned the trucks having a shudder due to the changed geometry of the trucks (GMs excuse memo I'd guess). Anyways, I told him I'd be inclined to think it had nothing to do with that being that it's went 14,500 miles without doing so. He explained they had to do it in the steps GM advised and I totally get that. I did not buy this truck from this dealer as they are a Chevy/Cadillac dealer but they have always treated me well. So as oh now I'm still optimistic.

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Part 2. Truck went in to dealership, I don't think they even looked at it tbh but it goes in at some point this week to have the torque converter flushed 3x, supposed to be a 5 or 6 hour deal. As we talked he mentioned the trucks having a shudder due to the changed geometry of the trucks (GMs excuse memo I'd guess). Anyways, I told him I'd be inclined to think it had nothing to do with that being that it's went 14,500 miles without doing so. He explained they had to do it in the steps GM advised and I totally get that. I did not buy this truck from this dealer as they are a Chevy/Cadillac dealer but they have always treated me well. So as oh now I'm still optimistic.

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Part 3. I dropped the truck off yesterday and picked it up this afternoon. The Chevy/Cadillac dealer have so far been extremely pleasant and courteous, no complaints there. I was told the internal parts were coated with something to prevent rust and was getting mixed with the transmission fluid and not doing well together. They flushed the system with 20 quarts and filled back with 8. Said I was supposed to drive for around 600-800 miles and that it may still do it a little during this period and that if continued to do it afterwards to let them know and they would proceed further. I also didn't buy the truck at this dealer but at another of the same name just different location and they have been nice enough to give me a loaner 2x already. I can definitely see wanting to do future business with this dealer, the service department can really make a difference. 4f4d8dbd0d46e556e6a9af118e9a71b3.jpg

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  • 2 months later...
On 11/2/2017 at 8:06 AM, JUS1MO said:

I really don't understand how GM gets away with selling these trucks with such problems that we all have. You would think that the buying public would hear about the transmission problems by word of mouth but they don't and keep on buying them like I did. I did not check the reviews on a new GMC truck before buying, I wish I had.  But now that I have it I am expecting GM to correct the problem but it seems that they want to use the excuse that the transmission has to learn my driving style, which I think is totally a cop out for not knowing how to fix the problem. You might think I am a little ticked of about this and you are correct. My name does not indicate that I can just get JUS1MO of these expensive trucks when I wish.

Proabaly because these sorts of transmission "issues" are common among manufacturers today, esepecially in the midsize and half-ton market where fuel economy numbers take precedent over soft , wimpy shifts. The biggest complaints over transmissions in the F-150 and Ram 1500 is hard shifts. The number 1 reason the 2016+ Tacoma is currently the least reliable midsize truck by Consumer Reports is because of transmission shift quality and behavior. The next Tundra that replaces the gas guzzling 07-18 version will have shitty shift quality, guaranteed.

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I have had my truck back to the dealer for an oil change and tire rotation. Since I was going anyway I asked them to try to do something about the shifting problems while they had it. Dropped it off a 8am and they called me a 11am to tell me that they could not duplicate the shifting problems that I described. I went to the dealership to ride with the transmission mechanic, and did for about an hour. While he was driving the truck shifted perfectly and we could not duplicate the problems. Kinda like a toothache until you get to the dentist office I guess. I left the dealer thinking, am I nuts or something, the truck drove perfectly all that day. The next morning it was back at the crap shifting and has done it on a regular basis everyday since. I am a loss for what to do now....

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On 10/20/2017 at 10:17 AM, jtjohnston said:

My 2017 GMC sierra 1500 6.2/ 8 speed with 4k miles just had TSB done on relearn of C3 return spring, i took it in because of the clunky noise on downshifts when coming to a stop. At first i thought it was fixed only to discover it wasn't, still clunky. It seems to downshift normally half the time and clunky the other half UNDER THE SAME EXACT DRIVING CONDITIONS. Also took in for rough idle, they adjusted the motor mounts then replaced them, no fix either, giving the truck some more time then I'm trading it in and never buying a GM truck again, what a damn joke this is for the amount i paid for this truck. Also forgot to mention they had my truck 14 days, i got lucky and they gave me a little Buick car for loaner, talked with others who had to endure longer times without getting a loaner. i hope eventually a class action lawsuit against GM is created for this transmission mess and the way they are handling it.

I hear you brother. i bought a 2017 sierra with the 8 speed. what a POS. Gm head office should get there thumbs out of there A** and admit theres a problem with these junks. Ive always been a gm guy myself. I had a new 2014 ram Laramie. with 8 speed also and the hemi engine. never even felt the transmission shift. it was so smooth. only reason i traded it in was because of the knob shift. couldnt get used to the dial. What a mistake. i made. Funny thing is i bought my truck in August and traded the Ram in to the dealership. I was taunted by the truck for months as the used car manager was driving around in that Ram till last week. he happend to live near my home. he also has 2 other Rams in the Driveway. what does that tell you about the guy he works at gm but drives Rams. Not saying there any better but at least im not driving around in a farm tractor. lol. iam just waiting till the 2019 Rams are out and will trade this junk in. i CAN LEARN TO LIVE WITH THE DIAL SHIFT.

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13 hours ago, JUS1MO said:

I have had my truck back to the dealer for an oil change and tire rotation. Since I was going anyway I asked them to try to do something about the shifting problems while they had it. Dropped it off a 8am and they called me a 11am to tell me that they could not duplicate the shifting problems that I described. I went to the dealership to ride with the transmission mechanic, and did for about an hour. While he was driving the truck shifted perfectly and we could not duplicate the problems. Kinda like a toothache until you get to the dentist office I guess. I left the dealer thinking, am I nuts or something, the truck drove perfectly all that day. The next morning it was back at the crap shifting and has done it on a regular basis everyday since. I am a loss for what to do now....

tHATS BECAUSE THEY KNOW THE PROBLEM AND HOW TO DRIVE IT TO NOT MAKE IT SHIFT HARSH. if you dont let off of the gas when your pulling away the transmission wont clunk to 2nd gear. but if you pull away from stop slowly and let off on the gas it will surely clunk. i have it down to a science i can make it clunk when ever i want. the techs know theres no fix so they tell you its normal bu\ecause they know how to drive it to not clunk. which should not be. one should not have to adjust driving habits to make the truck work as i should. Just GM hiding behind there design flaws again.. There is no fix even changing the transmission they will only put in the same one again. its a software issue. they want the vehicles to shift through all the gears before you even get to a stop sign because car manufatures are all about more gas milage. thats how they get kickbacks from the govt. Iam a small engine mechanic and when i took my truck in to the dealer for the shifting i went on a test drive with the software transmission Tech soon as he got in he said all Gm Transmissions are junk. especially the 8 speeds they get half a dozen each day with same problem. he said its a software issue but gm wont release a program to adjust the shift patterns and they are instructed to tell customers its normal operation.

Edited by benelli
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Benelli, I believe you are correct in your assessment of our situation. We don't have a leg to stand on in this. I will never understand how they keep selling these trucks at a rapid rate to unsuspecting people. I guess the word doesn't get out to the buying public. I certainly never heard a word about it before I bought one.

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