My own 8 speed problems & resolution

[Not1lost]

On 8/1/2018 at 7:16 AM, DCFisher said:

I have a 2106 Sierra SLT with the 5.3L and 8-speed transmission. My truck started to shudder when RPMs were between 1500 and 2000.  It didn’t matter what gear my truck was in. You would see the RPMs jump up about 300 rpm when the shudder occurred.  This started when I had around 28k miles on the truck.  This was due to issues with the torque converter locking and unlocking. GM performed the triple flush to remove the contaminates that were preventing it from functioning correctly.  The premature wear of the torque converter clutch plate is what contaminated my fluid and system. My truck drives much better now however I have only put around 4,000 Miles after the flush. I am concerned with the life of my TC and transmission. I plan to drive this truck for 200k plus miles.  The shifting is not as clunky as it was when the system was contaminated. Has anyone had long term success with the flush only?  Has the shudder come back after the triple flush?  I told GM I wanted a new trans. I was told the flush should fix my problem.  I don’t see how a flush adds the life back to my trans that was taken away by the premature wear on the clutch friction disc. I am thinking about trading for something else. I just don’t know what. I think I want a Duramax. 

I have a 2017 Canyon 4x4 SLE started doing the same thing at about 12000 mi continually getting worse! The worst shudder shaking is at about 55 steady speed with slight off and on exelaration to hold the speed in cruise or whatever. However it will do it at nearly any speed at times. Yes it helps when cruising at hwy speeds to downshift to 7th but that’s not what you should have to do! Besides it will do it in 7th too when it pulls just right up a grade.I thought the tires were out of balance and took it back to the dealer which re-balanced all of them and didn’t help at all. So I have another appointment next week. Going to give them a ride and shake their teeth out to show them what it is doing! The truck only has a little over 14000 mi. On it so this is completely unacceptable! And getting worse! I noticed the transmission temp. Will get up to around 150º at times and the hotter it gets the worse it gets; probably already damaged the internal parts... After all I have read on this forum and other about this I don’t think I’m going to go along with all the “we’re going to fix it crap” and tell them either buy it back or give me another “new” different kind of truck and transmission maybe like the Duramax you mentioned since it has the 6 speed in it. Any advice would be well taken on this issue. THANKS 

[Not1lost]

On 11/1/2017 at 11:05 AM, B R A D said:

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.

I have a 2017 Canyon 4x4 SLE started doing the same thing at about 12000 mi continually getting worse! The worst shudder shaking is at about 55 steady speed with slight off and on exelaration to hold the speed in cruise or whatever. However it will do it at nearly any speed at times. Yes it helps when cruising at hwy speeds to downshift to 7th but that’s not what you should have to do! Besides it will do it in 7th too when it pulls just right up a grade.I thought the tires were out of balance and took it back to the dealer which re-balanced all of them and didn’t help at all. So I have another appointment next week. Going to give them a ride and shake their teeth out to show them what it is doing! The truck only has a little over 14000 mi. On it so this is completely unacceptable! And getting worse! I noticed the transmission temp. Will get up to around 150º at times and the hotter it gets the worse it gets; probably already damaged the internal parts... After all I have read on this forum and other about this I don’t think I’m going to go along with all the “we’re going to fix it crap” and tell them either buy it back or give me another “new” different kind of truck and transmission maybe like the Duramax you mentioned since it has the 6 speed in it. Any advice would be well taken on this issue. THANKS

[Not1lost]

update: Took it to the dealer today and had the service manage ride with me to show him and have it documented that it will shake your teeth out while cursing. however when he got into the truck he said "I'll take a ride with you but I am well aware of this problem, I know what it is doing. I'm sure he does... he then told me they have to go through "the process" and do triple flush to see if that fixes it. said it probably would but if not they would put a new torque converter in it. I said if that will for sure fix it why not just go ahead and put it in there? GM says have to do the flush first... yeah$$$ I told him even if it fixed it how much damage has already been done to the longevity of the truck? Oh he said the transmission is fine... yeah sure. I had the lemon law book laying in the console so he could see it but said nothing. He knew what that meant... this whole thing makes me sick. I have always trusted GM and now they are trying to cover up an obvious recall issue. sickens me.

[Not1lost]

Update again:

Next visit to the dealership to do the triple flush on the shuddering transmission. while I was in the lobby waiting (only a few minutes) reading my lemon law book; the service manager came out and said it looks like we have an update on fixing your transmission. now GM is saying go ahead and skip the triple flush and replace the torque converter. well well, that's what I asked about to begin with if they knew it would fix it, why not!? so  they kept it about a week to replace the torque converter. I've driven it about 700 miles so far and it is very smooth, no shaking or shuddering so far. the thing that worries me is how much damage did it do to the rest of the transmission driving it with the wrong fluid in it and the torque converter going out (metal shavings pumped throughout the transmission) what is going to happen say 50,000 miles down the road? this was to be my last new truck since I am retired and on a fixed budget. I won't have the money to pay for replacing a transmission... concerned, don’t know what I should do even if it seems like it's fixed?

 

[pewterliftedz]

16 hours ago, Not1lost said:

Update again:

Next visit to the dealership to do the triple flush on the shuddering transmission. while I was in the lobby waiting (only a few minutes) reading my lemon law book; the service manager came out and said it looks like we have an update on fixing your transmission. now GM is saying go ahead and skip the triple flush and replace the torque converter. well well, that's what I asked about to begin with if they knew it would fix it, why not!? so  they kept it about a week to replace the torque converter. I've driven it about 700 miles so far and it is very smooth, no shaking or shuddering so far. the thing that worries me is how much damage did it do to the rest of the transmission driving it with the wrong fluid in it and the torque converter going out (metal shavings pumped throughout the transmission) what is going to happen say 50,000 miles down the road? this was to be my last new truck since I am retired and on a fixed budget. I won't have the money to pay for replacing a transmission... concerned, don’t know what I should do even if it seems like it's fixed?

 

•  

FYI.  You don't actually have a 8L90e like the silverado and sierra trucks do, this is the Silverado/Sierra sub-forum. Don't want people getting confused.

[Not1lost]

3 hours ago, pewterliftedz said:

FYI.  You don't actually have a 8L90e like the silverado and sierra trucks do, this is the Silverado/Sierra sub-forum. Don't want people getting confused.

Bad transmission is a bad transmission; same symptoms are the same symptoms; shuddering at highway speed is shuddering at highway speed no matter the letters and numbers you put after it. However, thank you for clarifying the issue. Hopefully nobody will be confused now.

[22mini20]

I don’t mean to bring up a older thread, but I do have a similar situation. I purchased a used 2015 Sierra Denali with the 6.2 and the 8 speed transmission. The vehicle is a clean truck one owner with 130k on it. Bought the truck with 132k on it. The day I drove it home (Jan 12th) I noticed it shifting hard due to it being a longer drive. Took it back the next business day they kept it and ended up replacing it with a new remanufactured GM TRANSMISSION, new caytalyst converters, new raidator. I picked it up on Jan 22 and I still have the hard shifts and hard downshifts that are enough to have my kids that are young what that was?. I told the dealer and had mentioned the tsb # 16-na-411. They said it would have the most updated software on it because they just replaced the transmission and they have to load the truck with software.? And the tsb is from 2017.  How true is this? Can’t they change the transmission and not do the updated software?? What are my other options

[MD11G200]

From my experience and In reading post to this form religiously for a year now my 2017 6.2 HP is a true clunker. From what I can tell you have zero options you have done more than most got a new transmission. I have been to three dealers for a total of four times. Only one had a service manager honest enough to tell me that you’ll never get rid of the clunking but the transmission will not fail. I’ve had the transmission relearned  twice and a flush. Are used to think the TCM was the problem but now I’m not for sure if it’s not Beau transmission and TCM combination. Not sure at this point if it TCM mod would even fix it. Love my truck on the highway but ad somebody On this website  put it it’s a stumbling drunk around town. Also have talk with somebody from General Motors three times that person was not an engineer and engineer will not speak to me totally frustrated and pissed off at the situation considering I paid 55K for the truck.  Please let me know if you get your issue resolved but unfortunately I think you’re in the same boat as most and will have to live with it . General motors needs their a$$ kicked for not acknowledging and fixing these problems.

[benelli]

On 2/2/2019 at 9:47 AM, MD11G200 said:

From my experience and In reading post to this form religiously for a year now my 2017 6.2 HP is a true clunker. From what I can tell you have zero options you have done more than most got a new transmission. I have been to three dealers for a total of four times. Only one had a service manager honest enough to tell me that you’ll never get rid of the clunking but the transmission will not fail. I’ve had the transmission relearned  twice and a flush. Are used to think the TCM was the problem but now I’m not for sure if it’s not Beau transmission and TCM combination. Not sure at this point if it TCM mod would even fix it. Love my truck on the highway but ad somebody On this website  put it it’s a stumbling drunk around town. Also have talk with somebody from General Motors three times that person was not an engineer and engineer will not speak to me totally frustrated and pissed off at the situation considering I paid 55K for the truck.  Please let me know if you get your issue resolved but unfortunately I think you’re in the same boat as most and will have to live with it . General motors needs their a$$ kicked for not acknowledging and fixing these problems.

Honestly your better off just trading in for another truck manufacturer. Your going to waste your time and get so frustrated. gm will never admit to a shotty design build on these transmissions. they should be ashamed of themselves. Thats why they offer 0/84 financing the banks get a a cut of the sales of the trucks. thats how they offer that financing. If you look at my earlier posts. not much can be done with the trans. they brush you off as normal operation. I will never buy a GM product again. I know every manufacturer has problems ,but you can usually get them remedied. I had a Ram with an 8 speed. could`t even here it shift through all the gears. spread the word about these crappy truck designs to everyone you now. Maybe Gm will wake up and do the right thing.

[Dough boy]

Well I’ve been bitten by the GM 8spd fiasco. Got the shudder and vibration going on. Service dept was able to recreate the issue and said oh there’s a TSB ON that so  just had the Triple flush done on my 18 Sierra Denali that has only 2750 miles on it. Drove it home shifted pretty well. Got home and parked it and decided to shift from Park into reverse and drive while sitting in the driveway and noticed a lot of chatter when shifting. Those noises weren’t there Prior to flush. Service advisor says you have to drive it for 200 miles to see if the flush worked. Yet now the transmission makes that racket when putting the truck in gear to drive. Got a feeling I’m going to be making several trips to the service department. 

[benelli]

On ‎2‎/‎27‎/‎2019 at 8:48 PM, Dough boy said:

Well I’ve been bitten by the GM 8spd fiasco. Got the shudder and vibration going on. Service dept was able to recreate the issue and said oh there’s a TSB ON that so  just had the Triple flush done on my 18 Sierra Denali that has only 2750 miles on it. Drove it home shifted pretty well. Got home and parked it and decided to shift from Park into reverse and drive while sitting in the driveway and noticed a lot of chatter when shifting. Those noises weren’t there Prior to flush. Service advisor says you have to drive it for 200 miles to see if the flush worked. Yet now the transmission makes that racket when putting the truck in gear to drive. Got a feeling I’m going to be making several trips to the service department. 

New TSB is 18-NA-355 not the old TSB which was triple flush the trans. If they did that triple flush that's useless. the new TSB requires a dump of the old fluid and exchange with Mobile 1 lv HP synthetic oil, but I don't think a trans oil change will fix the transmission issues these gm trucks have. its just a string along till warenty is up that's all. they cant even figure it out what does that tell you. Just a bad design.No oil or updates are going to fix this junk.

[huntr1117]

I got the flush and new fluid a couple of weeks ago. I've put about 600 miles on it and so far I'm very happy with the trans now. Shifting is great, shudder is gone, and haven't had the hard random downshifts. I was going to get the trans tuned, but now I'm thinking about saving some $ and just getting the motor tuned.

Sent from my SM-G950U using Tapatalk

[benelli]

56 minutes ago, huntr1117 said:

I got the flush and new fluid a couple of weeks ago. I've put about 600 miles on it and so far I'm very happy with the trans now. Shifting is great, shudder is gone, and haven't had the hard random downshifts. I was going to get the trans tuned, but now I'm thinking about saving some $ and just getting the motor tuned.

Sent from my SM-G950U using Tapatalk
 

Come back after a few weeks you’ll be pissed it will be back . Sorry just the way it is read all the previous posters posts. Everybody in the same boat or should I say wobbling barg truck. Lol

[huntr1117]

Come back after a few weeks you’ll be pissed it will be back . Sorry just the way it is read all the previous posters posts. Everybody in the same boat or should I say wobbling barg truck. Lol

I had the triple flush done about 8 months ago and was pretty happy with the results besides having the random hard clunk downshift. It stayed the same for the entire 8 months. Only reason I got the flush done again was because of the new fluid and I'm about to hit 36k. I was pleasantly surprised that the clunk is now gone and the shifts feel firmer now. I'm optimistic, but I'm happy with the current results. Hopefully the new fluid holds up.

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[benelli]

3 hours ago, huntr1117 said:

I had the triple flush done about 8 months ago and was pretty happy with the results besides having the random hard clunk downshift. It stayed the same for the entire 8 months. Only reason I got the flush done again was because of the new fluid and I'm about to hit 36k. I was pleasantly surprised that the clunk is now gone and the shifts feel firmer now. I'm optimistic, but I'm happy with the current results. Hopefully the new fluid holds up.

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Well you seem to be one of the few that have had good results. Bad design is a bad design . We should not have to go through all this crap after spending over 60 grand. Again they should be ashamed of themselves