TSB Seems To Fix 8-Speed Automatic GM Transmission Problems
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We’ve covered the problems of the eight-speed GM transmission on numerous occasions. In fact, we cover a class action lawsuit brought against GM back in April, complaints from owners, and even a recommendation that GM replace the eight-speed altogether with a new unit as quickly as possible. Now, GM Authority has learned that there’s a new fix that seems to be alleviating the eight-speed’s shifting woes outright.
As of July 8th, 2019, GM began using a new type of Mobil 1 automatic transmission fluid for the troublesome transmissions. Customers that complain of shuddering and harsh shifting characteristics in the 8-speed GM transmissions are recommended for a trans fluid flush. As of August 7th, GM dealers should also be flushing all potentially affected new vehicles on the lot.
According to TSB (Technical Service Bulletin) 18-NA-355, the latest update addresses “torque converter clutch (TCC) shudder conditions on 8L45 and 8L90” eight-speed automatic transmissions, RPO codes M5N, M5T, M5U, and M5X. Affected vehicles include Chevrolet, GMC and Cadillac vehicles, as follows.
Chevrolet
- 2015 – 2018 Chevrolet Silverado 1500
- 2015 – 2019 Chevrolet Corvette
- 2016 – 2019 Chevrolet Camaro
- 2017 – 2019 Chevrolet Colorado
GMC
- 2015 – 2017 GMC Yukon
- 2015 – 2018 GMC Sierra 1500
- 2017 – 2019 GMC Canyon
Cadillac
- 2015 – 2017 Cadillac Escalade
- 2016 – 2018 Cadillac CT6
- 2016 – 2019 Cadillac ATS
- 2016 – 2019 Cadillac ATS-V
- 2016 – 2019 Cadillac CTS (excluding V-Sport models)
- 2016-2019 Cadillac CTS-V
The issues with the 8-speed GM transmission are two-fold. First, some customers report the transmission shuddering frequently. Secondly, the shifts are very harsh between first to second, and then second down to first, especially when accelerating and the transmission is upshifting or decelerating and the transmission is downshifting. These conditions are most commonly observed under light and medium throttle applications, and as often during full throttle applications.
However, a new fluid flush appears to fix the issues, with some customers beginning to report a dramatic change in shift quality after swapping out the old juice. If the flush doesn’t fix the issue, the next step may be to replace the torque converter, which could be glazed.
The issue seems to stem from “moisture content in the transmission fluid.” As such, the old GM transmission liquid is swapped for new Mobil 1 Synthetic LV ATF HP fluid. Driving the vehicle for about a week or so improves shift quality even further as the new fluid cleans things up inside the transmission and the adaptive shift algorithms relearn various parameters.
This is obviously a big deal for owners struggling with their vehicle’s eight-speed. Hopefully the new fluid swap will provide a lasting fix.
Have you experienced shuddering and harsh shifts with your eight-speed GM transmission? Have you gone in for a fluid-swap fix? Let us know your experiences by posting in the comments section, and don’t forget to subscribe to GM Authority for 24/7 GM news coverage.
The problem has existed for 5 years. If it’s software they should fire every engineer and coder employed. I write software for a living (20 years now) and I’d be flipping burgers if I had a 5 year old bug. That said, I hope it is software so it can be fixed easily. I also hope my transmission isn’t trashed waiting for the new software. Those complete flushed every 15K miles might save it. I do #3 soon.
I’ve also gone to college for computer science, and later changed to information systems. I didn’t complete my degree, i’m looking to get back into that, but that’s probably irrelevant to this. Apple has bugs that have existed huge lengths of time on different occasions. Apple is pretty good, I’m just saying there’s instances where things aren’t fixed. I understand your statement though, it’s an industry where perfection is important. I said, it seems like there’s multiple things probably going on. I don’t know your situation, I haven’t driven your vehicle, or looked at it. There could be something, and the dealer would probably be your bet, since they have the resources. I’d say it can still be software, and it can still be flawless, however they have to change things to satisfy customers demands. Todays vehicles rely heavily on computers, software, and sensors, and many systems communicate to others. Stabilitrak looks pretty complex, if you look into it. The software/ computer is what is going to control the transmission operation. If something is off, either by bugs, or if they just don’t have their settings to meet customers satisfactory needs for operation, it can cause the shift issues. If what you experience are the vibrations, or other related symptoms, it’s probably the torque converter. There are other things that can cause the vibrations though. It’s just crazy how the one guy put a custom tune on his, and said his transmission is flawless now.
I was told by the service manager that at least some of the software is prioritized by the EPA. and cant be changed. I think the AFM auto fuel management cant be changed. if it messes with the rpms. causing
the trans software to malfunction.
I just had my 2019 Canyon serviced, yet again, for the stuttering effect when on an incline and the hard shift from 1st to 2nd. This makes the second transmission flush in less than 1.5 years. Also, my AC quite functioning and was serviced once again. This time it was said a totally new software package was uploaded for it. I picked up my truck today.
I went all of the 2019 summer with no AC. The AC was repaired along with a complete newly installed rear-end. The whining noise heard from the day-1 test drive was discovered to be a faulty pinion gear (9 months later). Also, there were incorrect shims on it. My truck sat at the dealership for 94 days straight last fall for that issue. The timing was worse because GM had went on strike. Also, when GM received my letter that included the words (non-conforming vehicle, please make your final attempt to repair it) a new rear-end showed up all the sudden at the dealership that was servicing my vehicle.
I have had the truck since Jan 2019, but have actually only had it in my possession for 1 year 2.5 months. It spent 3.5 months in the shop. I am curious to know if the transmission flush will end up being a yearly required service. Also, I am willing to bet my AC will fair again before the year is out.
I guess GM has no concept of image and reputation and what it can do for your bottom line. It has been said a reputation can make you or break you. Take Toyota their vehicles may not be any better than anyone else’s but their reputation make the sales for them. You would think with all the problems and all the years GM has had problems with this transmission they would do everything in their power eliminate those problems.
The bad reputation and negative press from these problems has to be causing them to lose customers and hurting their bottom line. There is an old saying if it aint broke don’t fix it. GM need to get on the other side of this and go with if it is broke fix it.
From the various TSBs, it seems to be mind blowing to their engineers. Today’s transmissions, are a lot more complex than yesteryears. You have way more computer, and software development. Through the various attempts for TSBs, it appears there’s an effort on their part to attempt to solve the issue, otherwise there’d be nothing. It seems they can’t figure out if it’s software, physical/hardware related, or the latest with fluid. What I do know, is what I’ve seen. Someone on Internet forums changed their transmission fluid, they got a shop(not a GM dealer), to put a custom tune(software) on their transmission, and they may have changed the torque converter also. They later reported it was fine after all of that. I’m going to say, it’s probably something that is different for every vehicle as well. A vehicle can be fine, and none actually have this issue, which I’ve seen reports out there, or they just need improvement on the software calibration variables, or it can need it all. I’ve read some comments and reviews that said just the fluid change by itself helped some vehicles, and the customers are satisfied with it. By the sound of everything, it seems like the majority would be satisfied if they tweaked the software a bit. There’s a comment on here that said they heard an update is coming. For the other vehicles with hardware problems such as torque converters, I have no idea. I’d say there could be a certain percentage that got the transmission hardware changed prematurely. I get everyone is pissed, I would be as well. I just like to look into issues, and go for both sides when necessary with supporting evidence. From the sound, it seems once they get the software variables right, everyone gets a rebuild of some sort, and fluid change, everyone with complaints should be good to go. A lot of manufacturers go through this process, even Toyota at times.
Very well said, hopefully a software update if needed will solve this issue. Also like what you mentioned that something along this line is coming. It’s about time every second person is complaining. Myself for one will be on board for this solution.
I’m not for certain one is coming, I just saw it on this comment section. They said they talked to their dealer. Hopefully it’s true. The transmission seems like it has potential. They just have to figure out what’s going wrong, or what’s making everyone unsatisfied with it. It seems everything that has come out of engineering makes sense, although it’s a mess of different diagnostics and solutions, that just doesn’t work yet, especially for everyone. The person I’m referring to, what he did with the custom tune, makes sense as well. The 6 Speeds seem pretty good, and the new 10Speeds seem good from what I’ve read from a majority of comments and reviews. I think the 8 speed has potential, however I’ve never drove one. I just don’t think it’s a lost cause.
I just recived my truck back after sending it in the second time for the transmission. 2016 Sierra 1500 8 speed. The first time I sent it, was for the “rumble strip” issue. They did the flush under warranty. problem went away for about 100 miles. The truck then began having a lot of trouble in higher gears, almost felt like the engine was misfiring when accelerating, but it is actaully the convertor not know when to lock up and the transmission not knowing when to downshift. I sent it in the second time, and the technician test drove drove it, and immediately felt it. He didnt sugar coat it, and basically said GM will say this is normal. Even though we both agreed it was undrivable, he was correct, GM did the fluid flush again, after just having it done. The truck actually does drive fine now, however I cant help but assume that history will repeat itself. I am nearing the end of my warranty and I feel like I am going to be stuck with this problem out of pocket. Not having a job right now doesnt help that.
Yeah, I can understand your situation. I believe if it happens again, they’re told to look at the torque converter, and replace if necessary. That’s based on the documentation off of the NHTSA website. Before the required flush came out, I believe they would’ve just replaced it. Before that, I think it was software. Also, different technicians may try different things as well to try to solve the issue. If you went to other dealers there’s a small chance they would’ve maybe replaced your torque converter, or did a software update, they’re told not to, but I’d imagine not everyone follows that. It’s tough to see what they’re thinking. In all aspects of it, it makes sense what engineering is thinking, although they just don’t have it spot on yet.its really a tough case. The 8 sounds like it has potential, they just have to figure this out. Sorry to learn about your job, and situation. Hopefully it all works out.
I understand there will sometimes be problem with any products and or equipment. My concern is this problem has been going on way too long and handled very poorly. GM need to figure out a way to solve all and any issues with this transmission for the good of the company and the customers. When you get a reputation for poor quality products and poor customer service that is hard to overcome. When you do have problems how well you handle those problems make a big difference.
Absolutely, I agree that reputation is everything, and that how you handle it goes a long way. Every company has a positive, and a negative reputation. It’s usually how it is. This has been going on for awhile. They are aware that there is an issue of some sort. Which is partly why they tell dealers to reflash the transmission module(usually with revised software), change the torque converter, or do a transmission flush,etc.. Some dealer technicians may know a cause, but they depend on engineering to be able to fix your vehicle,without engineerings word, that’s how dealers will tell you things are normal. At times, normal just can mean, how every unit is. All of these bulletins from engineering make sense, to be the cause of the complaint. Who knows exactly why it’s taking so long to get an exact remedy. What has happened is they have multiple causes they have identified to possibly cause the issue, and they have mixed results for every one of them, including some vehicles being completely fine since day 1. It’s hard to totally fix something if a complete cause hasn’t been identified. It could mean everyone needs transmission modifications/torque converters, new fluid, and a different/new calibration of the software. They might have to change torque converters completely. Could they be avoiding things? There’s a possibility, it just has evidence of multiple attempts to get it right. The company is a little strange today. They want to do the right things, however they also go back to their old ways at times. I wouldn’t expect anything, however I can almost see that once they have a cause there’ll probably be some kind of warranty on just that, or potentially a recall. It sucks, and I’d be pissed as well. Hopefully something will come up soon.
I certainly agree that reputation is everything and I am on my last Cadillac. My CTS lags and hesitates waiting for the transmission to catch up. Cadillac changed the fluid but I could get them to change the torque converter. That was even after contacting Cadillac Reps and GM Reps. Pathetic customer service for a high end car. Actually at this point I don’t consider it a high end car I consider it a high priced low value car that runs poorly. Maybe GM figures that by the time they admit that there is a huge problem with this trans most will have unloaded their cars and they wont have to fix as many. I am very disappointed in Cadillac.
OMG! I just got a 2017 Cadillac ATS and it is a beautiful car… Then I got the vibration or shudder as everyone calls it. I bought it from a Cadillac dealer as a certified Cadillac. I can’t believe that they didn’t service the Transmission before selling it. This might very well be my last car purchase and I went big, Cadillac! I traded in my Nissan because of all the stories of the CVT Transmission being crap … LOL … and I ended up with the same thing. Very disappointed in GM. I am going this Saturday for a transmission service. I hope it is covered by the warranty and I hope it fixes the shudder.
I had this exact issue with my 2017 CTS 3.6. I did two transmission flushes. The first before GM came out with the “correct” fluid and flushing equipment. The second with the correct fluid and flushing equipment. I had the shudder and the weird hard shift and low speed surge when car shifted from first to second. Neither flush corrected the problem. I did some online research and found an old TSB indicating the 8L45 transmission may require a new torque converter to fix the problem. GM did not want to do this, but I was quite insistent. They had me in a loaner for 6 weeks….it was a new CT6 so I didn’t mind. Guess what…..after 14 months of messing around with flushes and 6 weeks in a loaner the new torque converter fixed the shudder and the hard 1st to 2nd shift. You need to insist in the torque converter if the flush does not fix your problem.
Geez. What did I get myself into! I thought owning a Cadillac was like the American dream. 😢
Boy, Isn’t that the truth. I thought but he same thing about owning a Cadillac. I am very disappointed. I‘ve had nothing but problems with my 2018 CTS transmission and all I could get Cadillac to do is the triple flush. I couldn’t get them to change the torque converter. It’s a double whammy for me because I also have a 2016 Corvette with the 8 speed trans. It just started the shuttering and RPM variations a couple of weeks ago. I had the triple flush performed and so far so good. I just hope that it takes care of the problem for good. This entire transmission situation And GM’s lack of caring to remedy the problem has really turned me off on GM products. I just replaced my Silverado with a Dodge Ram truck and the Cadillac is most likely next to be traded for a non-GM product. I have had 49 cars in my 50+ years of driving, most of them GM and that loyalty streak will soon be coming to an end.
I’m an Attorney in a rural community in PA. I do a lot of Municipal work. Many of the leaders in Township and Borough government are farmers and blue collar men and women. I want to drive an American luxury car. That leaves me with Lincoln or Cadillac. My wife has owned BMW, Mercedes, Lexus, and Audi. Each has its good and bad. Other than the Lexus each has been high maintenance after about 50,000 miles. None of the brands I mentioned drive and handle as well as the CTS. It is, hands down, the best handling mid size luxury/sport sedan I have driven. It is also comfortable and quiet. GM just has a lousy transmission on its hands with the 8L45. Now that mine is fixed I would take it over any of the others.
I agree with you Anthony that the CTS is a nice car that ended up with a bad transmission but it’s how GM/Cadillac remedies the problem which will dictate the outcome of their reputation. So far they haven’t been performing in a particularly stellar manner. If they want to save their reputation they need to take care of their customers that put up $50, $60, $70K to more for a vehicle that has lackluster transmissions. If it means replacing the transmission so be it. Will it be costly? Absolutely. Will it help save their customer base? They stand a much better chance of saving their base than what they have been doing so far. They are on their way to losing me for good. I love everything about my CTS but when it hesitates or lags from a stop in the middle of an intersection or possible railroad tracks and they wont fix the problem it’s time to cut my losses and move on. It is at a considerable expense though and one that doesn’t leave a good taste in my mouth for Cadillac or GM. I also like my American cars. I can replace the Cadillac with something American to be sure but I am not so enthusiastic about what to replace my Corvette with should the fluid flush not permanently remedy the transmission problem.
I have the same issue with my Colorado. I’ll pull out into traffic, and nothing happens, my truck just has this weird throttle delay. It’s a seriously dangerous issue, and GM should be held accountable for selling these garbage transmissions.
I have found that I can somewhat minimize the hesitation by coming to an absolute complete stop and not a rolling stop. It’s still not good and yes, dangerous.
I’ve had 2 flushes. Hard shifts never returned after the first. Shudder hasn’t returned yet after the second (latest TSB with blue fluid) but it took 10,000 miles to return the first time. I’ve been driving in M7 exclusively to disable AFM and I don’t experience delayed shifts anymore. I spent a weeks doing the same thing in D and M7 and it is consistent that D cannot decide which gear to use in some scenarios while M7 has not issue.
I’m scheduling a dyno tune after intake/exhaust mods and will have an AFM delete included in the tune.
2015 Sierra 6.2L at 34,000 miles.
Hello, I am on my second flush as well, however my issue came back after only 300 miles. Interested to hear that leaving in M7 has improved your shifting. How does this work, instead of drive you put it manual gear 7, and let it automatically shift itself?
I had a Diablo tune on my 2018 Silverado, with AFM turned off and it didn’t make any difference with the shudder. They ended up replacing the torque converter which improved the issues. Then after 1000 miles it’s started to shudder again, so I brought it back over 2 weeks ago. Apparently, there’s a temperature sensor in the tranny that went bad. The part is on back order due to the strike and COVID. That’s what the service person told me at the dealership. So, I’m waiting and waiting. He said that’ll fix it? Somehow I don’t by it.
Haha. They did my temp sensor at the send flush as well. Its been about 200 miles, so far so good. Temp sensor sounds like the new “software update” scam for this problem.
Yes, when I start the truck I put it in M7 and let it shift the same as if it was in D only it never drops to V4 mode.
This has nothing to do with TC shudder. I tried M7 based on another online post specifically for the delayed shifts and it helps for my specific truck. I do not drive much and the shudder might come back in 5000 or 8000 miles. If it does that will be the 3rd time and I’ll insist on a TC replacement. The dealer knows me quite well now … made a huge stink the 1st and 2nd time with printed out TSBs in hand. I owned the truck less than a year when a valve spring for cylinder #4 broke resulting in a complete engine swap. A few months later, free full body massages while you vibrated down the road 50-70mph … leading to flush #1.
I was told by the service manager that at least some of the software is prioritized by the EPA. and cant be changed. I think the AFM auto fuel management cant be changed. if it messes with the rpms. causing
the trans software to malfunction.
I was told by the service manager that at least some of the software is prioritized by the EPA. and cant be changed. I think the AFM auto fuel management cant be changed. if it messes with the rpms. causing
the trans software to malfunction.
2018 Colorado has 5,000 miles. Has been shuddering for awhile. Dealer just changed the fluid and it appears to be working much better. From my reading though, this is a just a short term fix???? I’d love to hear if this fixed the issue for others. However, the dealer did tell me I had to drive it for 300 miles, and ‘if’ it shudders, they will replace the transmission.
No mention at all about replacing a torque converter.
Is anyone having issues with the NEW 8-speed transmission, or is this a permanent fix?
I see the class action suit against GM has been dropped — I’m assuming because they are offering a fix. Good for them for doing the right thing.
The class action lawsuit has been dropped? Where did you hear that?
Where did you hear that? Links…
Looked at classaction.org website…..suit is still pending however I read a report on the internet that GM is going all out to fight it…
I am on my 2nd transmission flush. I am driving a 2019 Canyon, and I bought it with it having 15 miles on it. It appears this will be a yearly maintenance task for me once my warranty runs out. (Via a BBB case I placed last year about the rear-end whining noise from the faulty pinion gear, I was awarded an extended 5-year warranty and they paid three payments to cover the 94 consecutive days my truck sat in the dealership for the repair.)
Also, this is going on Summer #2 that I don’t have functional air conditioning. My truck has been in the shop for 2 months this year. Just got it back yesterday, and this makes it the 4th reprogramming event to try and resolve it. The new bulletin suggests “with the new programming, customer will need to adjust the hot/cold knob to a warmer setting each time the AC system freezes up to allow it to thaw out. I said, “Nowhere in the driver’s manual in my glovebox does it say do that.” I live in NC. When the temp is over 80 degrees, the AC freezes up within 10 minutes of use. I can recreate it on-the-fly. I will test it Monday when I return to work.
My job has me on the road during the day, and I use my truck.
Any way, I know that was off topic, but thought I would share it in the event someone else is having the same issue with their GM vehicle. Oh yeah, they just replaced my radio. The touch panel stopped responding. So, I shut the truck off and cranked it to troubleshoot. The screen never lit back up. Here’s the kicker. When I would turn the truck off from that point, the screen lit up briefly. I recorded the event and the GM techs in GM land were perplexed. So, they shipped a replacement radio.
Going back to the transmission, the gap between the two flushes is 6 months. There are 20,000 miles on it now. I expect by Christmas the shudder will return.
2018 Colorado with 5000 miles shuddered terribly. Dealer replaced the trans fluid and it appears to be driving much better. Is this a permanent fix or temporary fix? what have others experienced with this?
No mention to replacing the torque converter.
I was told to drive it for 300 miles, and if shudder reappears, bring it back for a transmission replacement!
Does the NEW 8-speed transmission permanently fix the shudder issue? Has anyone had it long enough to verify this?
From my brief search on the internet, I found an article that the class action suit against GM for this issue has been dropped. I’m assuming because GM provided a fix? If so, good for GM for doing the right thing.
My 2018 Canyon was shuddering for a couple of weeks. Not sure what it was. Took it to GM and they put the Mobile trans. In after flush. He said it should stop .. give it a 200-300 miles. It shouldn’t do it again but if it does to bring it back. It’s been at least 300 miles. So far so good. But if it does it again, I’m getting something else.
IMO anyone who has been in at least three time with transmission problem on a vehicle less than five years old and is still having problems should get a new 10 speed at no cost to them. Know if a company did all they could to show that they appreciated my business I would be back and if not I won’t be back.
I have a 17 Yukon XL Denali. OriginL problem started (shuttering) @ 46,000 miles. Mobil Fluid change was completed, zero issues until a few weeks ago. Pause/hard shift started between 1st-2nd started @ 59,000 miles. Unfortunately, after 2-days of technician said he was unable to duplicate. The Service Advisor (solid guy) acknowledged he felt the exact conditions that I complained of. Without wanting to argue, I asked that his acknowledgement be stated in the report.
It was not…. Service Manager acknowledged my complaint but said GM has not provided them direction, they can’t perform service in which they won’t get reimbursed for.
I told him that a False Service report had been provided and said that all I wanted was another fluid change; or a torque converter change based upon countrywide Group experiences.
That didn’t happen. I have filed a complaint thru GM and the owner of Mark Christopher Chevy/GM/Cadillac.
I’ll advise as to any (if any) results.
It’s a real shame and quite frankly BS that GM isn’t acknowledging that there is most certainly a problem with these GM transmissions. As stated in earlier posts, I have a 2018 Cadillac CTS with more Of a hesitation than shuddering. Had the triple flush but it didn’t help. I couldn’t get Cadillac to change the torque converter no matter how hard I tried convincing them that the converter could be glazed. About a month ago my 2016 Corvette started the shuttering. Chevy performed the triple flush and added the new fluid. So far so good but everything that I have read sure seems to indicate that there’s a good chance that the problem could return. I had a 2014 Silverado but it had the 6 speed so no problems there however since I couldn’t get any satisfaction on my CTS from Cadillac/GM I decided to trade the truck in on a new Ram. Why should I show any loyalty to GM? The Cadillac is as good as gone sometime this summer since my wife will need a new car. It will be a non-GM car. Time will tell on the Corvette. Keeping my fingers crossed there. My point being with this long story is that GM is creating an angry base of disloyal customers by not doing right by them and replacing the faulty transmissions.
What are they going to replace it with? If they take the 8 speed out, a new one, that is the same will go in. So if the existing one has a potential design flaw, the new one could have that same flaw. Granted they’ve had 8 speeds with 0 complaints and flaws since day one, so perhaps someone would get lucky with a replacement. They did replace torque converters at one point, and apparently the problems still persisted so they are probably advising not to replace them. There’s a new bulletin that says not to do so, unless really necessary. I have 7 GM dealers in my area, there’s a chance at least one out of the 7 their transmission techs would say something different than the others. The engineers seem to be running in circles trying to figure it out, evidenced by the multiple TSBs and procedures to figure it out. I’d say that sense they are attempting so many procedures they are acknowledging the issue. There’s been software updates, there’s been physical things replaced like the torque converters, there’s been fluid replacements. Perhaps it’s not even the transmission at all. If a vehicle has AFM, I’ve read that people are tuning that out, and remedying the issue. I’ve read where people replaced the fluid with Amsoil, and that helped. I’ve also read where someone that did that, also had a shop put a custom tune on it, and that helped. Who knows, there’s so many variables involved with people having 0 issues, people having multiple issues, people having some issues, people going in having their issues resolved permanently, some going in multiple visits, some looking into what they can do with custom tunes, the few that deactivated AFM, and then all the different procedures GM attempted. All of that could be why there’s not a full fix that’s 100% final.
How about replacing it with a GM transmission that hasn’t had these problems? 6 speed, 10 speed? I don’t care, but we shouldn’t be told that these transmission problems are normal!
That could be very possible, but I’m sure for some applications on certain models they’d have to do more modifications than just swapping a transmission for a different type. I know that they have the new Camaros with the 10 Speeds now instead of the 8, my Gen5 Camaro has the 6 Speed. They also have 6 speed, 8 Speed, and 10 Speeds on the new trucks. It’s very possible, but the question would probably be the difference in how a different transmission would operate with the vehicle in question. If you wanted that, you’d probably have to also do it yourself. I wouldn’t see any manufacturer that would do that through their dealerships. The only way that would also maybe occur is if the engineering team deemed that 8 speed is just no good. Even then, it would probably be a redesigned 8speed. It doesn’t seem that would be necessary though, a transmission is made up of multiple parts. So, even if a transmission is said to be bad, you just change the parts/rebuild it, and they’re usually good to go if done correctly. As far as what the word “normal” means, who knows?Perhaps it may not seem normal to the customer, however from the engineering side, everything seems to be operating as it’s supposed to by design, and that could be without a potential fix. Once a fix is applied that probably becomes “normal”. Then it also goes back to the technician thing. Like I said, one transmission tech may say something different from another. I have 7 GM dealers in my area. There’s a chance you’d hear something different.
These transmissions are not right. No one at GM is trying to fix them saying the jerking and bumpy ride is normal. Changing the fluid is not the cure. It seems to me it’s in the programming of the computer. The torque converter is not able to lockup causing the shuttering . The engineers probably can’t change this do to the EPA ratings.
This just my thought on this.
That’s probably correct. I’ve actually stated the same thing previously. If you go back in the comments, someone said that they heard from a service manager or representative at their dealer that GM is working on a new software update. If that’s the case, after they apply the update, and someone still has complaints afterwards, they’d probably say once again that it’s normal, unless something is wrong. They’re not acknowledging the transmission is absolutely fine. It seems like they’re saying based on everything the way it is at the moment of complaint, that it’s normal as in all the transmissions tested by complaint are similar, and there’s no remedy from engineering at the moment of visit. If there was an actual problem, and the dealer was trustworthy, and the technicians were good, then you’d more than likely hear what they’ve found to maybe be the issue. For example, if you go in, and the torque converter is shot, then you’d have a high chance of getting a new torque converter.
The new Mobil ATF fixed the shudder issue in my Colorado, but it doesn’t fix many other issues that myself and many others have had. My Colorado’s transmission is the worst transmission I’ve ever driven in my life. Right now it’s doing this horrible hard shift between 1-2 and 2-1. It sometimes feels like I’ve been hit from behind. My truck has 59,000 miles, warranty is about to expire. Buying this truck was a mistake, I wish I had known before I purchased. I’m so glad that I spent my money to be Chevy’s guinea pig while they wasted time and took forever to figure out how to fix this shudder issue. I’ll never buy another GM product, especially after reading this little gem: “GM claims the problems with the transmission do not fall under the factory warranty, as it is a design defect and not a manufacturing defect”.
I have a 2017 Yukon Denali and still have problems with the transmission lunging from first gear. Not all the time and that is the biggest problem. According to GMC it is their normal range of acceptability of performance. Without my seat belt on it would have thrown me through the windshield. Kinda like driving a bucking bronco, at times. Sometime it goes for days without doing it. Yes, they finally changed the fluid but it still acts up more violently then it had in the past. So, buy American made cars, get crap for a warranty, pay $65,000 or more for a car that is, at times, scary to drive. So, thanks for nothing, GM, for knowing you have a problem and not fixing it!!!!!!!!!!!!!!!!!
I have a 2016 Sierra SLT AllTerrain version with 90,000 miles. When I have the 4WD selector switch set on 2WD, the transmission temp goes to about 120 degrees and the shift between 1st and 2nd is harsh in both directions. I can turn the
switch to “Auto” and the transmission temp goes to around 175 degrees and the shifting is normal. Could it be that the transmission fluid cooler is keeping the fluid too cool and it works better at higher temps? I honestly don’t even know
what the “Normal” operating temp is for Transmission fluid.
I don’t own one of these trucks, and I wouldn’t know anything from the engineering aspect of it, however the temperatures seem fine. The increase in temperature probably comes from the transmission having more activity in 4WD mode. I have a 2015 Camaro RS with the LFX V6, and 6 speed auto. It seems once the transmission gets up to temperature, it favors around the 180 degree mark. The shifting sounds like either transmission, or transfer case( which is the mechanical part of transitioning between 2WD, and 4WD. On the lucky side, you probably just need some maintenance on the transmission and/or transfer case. On the unlucky side, you might be looking at some kind of repair with the transmission or transfer case. Seems more like the transfer case is to blame, but I’m not sure.
Ok, so May 2019 I take my Denali in with shuddering and hardshifting problems $700 later transmission fluid has been changed. June 2020 here we go again same issues, oh it’s the Shifting Harness $816… today I jump in my car to leave get out of my driveway and nothing! Can’t even manual shift – could have been in a serious wreck – back in the shop. All work has been done at the dealership, they had to send a tow truck. Glad my kids and I were not hurt. I don’t have to express my displeasure- bet you can guess. 2016 Yukon XL Denali.
You really need to join the class action lawsuit youshould not have to be paying for all this stuff out of pocket. Especially for their oil change I can’t believe GM is charging you for that when they are putting that in all their 8 speed transmission vehicles. Seems like the only thing that might help for awhile is to replace the entire transmission but that will probably cost you five thousand. Once you get it going sell it don’t buy GM anymore.
Excuse me Trent this Mom is probably not a child- I bet she can make her own decisions now. Are you a representative of a law firm filing suit against GM or maybe a salesman for Hyundia? Why don’t you just send her your fortune teller’s card & give her a free reading?
Just bought a 17 Yukon Denali xl with 32k on it I’ve only put 300 miles on it and its shuttering in 1st gear under 30mph I wish I saw this forum first I wouldn’t have bought it beautiful truck but 50k to shake and wobble feels li3ke a slap in the face for an American product.
Take it to a GM service department, it’s still under warranty. Make them do the transmission flush and put in the new Mobil 1 ATF. If they won’t do it, then go somewhere else. That’s what I had to do. There’s a service bulletin that instructs GM to change the fluid if it’s shuddering. Don’t let them tell you it’s normal.
I had my second flush done. The first one they used Mobil 1 ATF. The second one they used Dexron 3. I asked about it and they said the service bulletin has been changed and Dexron 3, supposedly a new formulation, is being used now