General Motors is looking to have a class-action lawsuit dismissed that alleges there are defects with its 8L45 and 8L90 eight-speed automatic transmissions.
The lawsuit, filed in the U.S. District Court for the Eastern District of Michigan, alleges GM’s eight-speed automatic transmissions may shift violently into gear. The filing claims the problems are caused by some type of hydraulic systems failure, which can wear down the gears and allow metal shavings to become caught within the transmission. GM has sent technical service bulletins to dealerships, which plaintiffs say are an indication the automaker has known about the defects since at least 2015. The lawsuit also claims GM’s suggested fixes, such as flushing the transmission system, are only a temporary solution.
8L45 transmission
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. According to GM’s motion to dismiss, which was obtained by Car Complaints, the automaker’s warranty is only for vehicles that have “a defect that is so basic it renders the vehicle unfit for its ordinary purpose of providing transportation.” It says the plaintiffs in this class action suit “make only conclusory allegations that their vehicles are ‘unfit for their ordinary and intended use,’ but allege only inconvenience and mild discomfort.”
8L90 transmission
It also points out that no injuries or deaths have been attributed to the problem and that no one has stopped driving their vehicle completely due to the rough shifting issue.
The 8L45 and 8L90 eight-speed automatic transmission was used in a wide variety of previous-generation GM vehicles with rear-wheel drive or four-wheel drive. The full list of affected vehicles in this class-action suit includes:
- 2015-2017 Cadillac Escalade
- 2015-2017 Cadillac Escalade ESV
- 2016-2019 Cadillac ATS
- 2016-2019 Cadillac ATS-V
- 2016-2019 Cadillac CTS
- 2016-2019 Cadillac CTS-V
- 2016-2019 Cadillac CT6
- 2015-2019 Chevrolet Silverado
- 2017-2019 Chevrolet Colorado
- 2015-2019 Chevrolet Corvette
- 2016-2019 Chevrolet Camaro
- 2017-2019 GMC Canyon
- 2015-2019 GMC Sierra
- 2015-2019 GMC Yukon
- 2015-2019 GMC Yukon XL
- 2015-2017 GMC Yukon Denali
- 2015-2017 GMC Yukon Denali XL
Subscribe to GM Authority for more GM legal news, GM recall news, GM safety news, and around-the-clock General Motors news coverage.
Source: Car Complaints
Comments
is gm trying to be “sarcastic”?
Honestly one of the worst trans I have had in a vehicle. The 8 speed trans in my new RAM limited is really nice and shifts smoothly.
Though after a flush of the trans it did get better, but was still bad.
Interesting view…
Actually there is nothing wrong with the transmission.
The problem was with the fluid absorbing moisture and it would affect the converter clutch.
It took time to identify the issue and created and test the fluid but they now have it with Mobil one blue label.
If you present the vehicle it generally resolved the issue. If not the dealers are directed to replace the converter.
This lawsuit is not going yo fix anything. If you have the shudder or even if you don have the shudder the dealer will flush the transmission upon request if it is pre March 2019 build. The TSB is out there and they know about it.
This has taken the problem from the top spot on the forum to just an occasional mention.
This lawsuit is more about the lawyers just trying to get rich off this and leave you with a free oil change or discount on a future vehicle while they claim millions in legal fees.
Skip the lawyer and just get the fluid flushed on the GM dime.
Mine was done last August and has never been better.
Except 2016 vehicles can be going out of powertrain warranty. If GM were to promise a free flush and remedy – I think you’d have better standing to bash critical coverage of this.
That’s the problem with TSBs, or “silent recalls” = customers can’t access them and they are merely guidance after the warranty runs out.
If this was Tesla, it would be a courtesy repair credit – even though that helps Tesla’s balance sheet… it also helps customer loyalty. Big time.
The TSB are easily found on numerous sites and forums and can easily be found.
If you can’t find it you are not looking.
GM has been extending things in some cases to take care of those out of warranty in some cases.
As for Tesla. If GM only held 1 to 2 percent of the market they would me more flexible too. Tesla will lose much of this as they grow and if they are still around.
Frankly that’s just not correct. Mechanics still pay for TSB access for a reason. It’s an anti-consumer trend that needs to end. Someone needs to either catalog the TSBs like RECAP did for the federal courts – or the laws need to change to compel publishing of TSBs to consumers.
“GM has been extending things in some cases to take care of those out of warranty in some cases.”
If you believe that is happening on a widespread basis, there would be a customer courtesy program posted… by GM Authority. Which you just attacked for covering this too harshly. Catch 22 there.
Even anti-Tesla, Maximum Bob Lutz has admitted Tesla turned the tide, you’ve gotta drink a lot of Kool Aid to believe otherwise.
Not true the TSB’s are available from the NTSB, From GM Techlink, from this forum, from every forum of each model posting the most common issues.
Just google 18-NA-355 and you will see how easy it is to find like most bulletins.
Tesla has a well documented history of service issues. They are not walking on water any more than anyone else.
If they approve my post with the web links you can see how I can back all this up with documentation. The links locked it up for approval.
Note one site is this very one who often reports TSB info.
Today with the web little info hoes unreported anymore with bulletins. In fact many forums have specific threads posted and updated by dealer staff.
NTSB only publishes safety TSBs. Anything not deemed a safety hazard is not posted, other than header information that says nothing useful.
Techlink is as laughable as a compliance car. It is just marketing for Techline Connect. Ask yourself why Techline Connect exists if Techlink was actually usable by the public? The answer is obvious, it’s intentionally unusable.
When did Tesla start using transmissions?
As the owner of an affected vehicle, I am somewhat more than idly interested in your assertion that there is nothing wrong with the transmission.
Based on various forum posts, I am aware of two (I believe separate) issues: 1) shuddering, and 2) hard shifting.
I had the shuddering issue, and got the flush with the blue label fluid shortly thereafter. It seems to have resolved that issue, but I have not put a lot of miles on it since, so can’t be sure just yet.
I have not had the hard shifting issue that many people have reported.
I was under the impression that the August 2019 revision of 18-NA-355 was only covering the shuddering issue, and not the hard shifting. Are you claiming that both issues are corrected with 18-NA-355?
I just accidentally gave my post a thumbs up and can’t figure out how to undo it. 🙁
The fluid change was directed at the shudder. But those of us who had the 1-2 hard shift found as we drove it on the new fluid the shift has gotten smoother.
Mine went away and I waited for this winter to see if it came back. In cold conditions it is a little firmer in the first mile but it goes away. It is nothing annoying anymore.
To be honest after the change I have no complaint of the transmission.
Might also note GM is not the only mfg with shudder issues. Many MFGs have had converter clutch issues due to moisture absorption in the fluid.
It used to be we had two fluids and today just look at all the fluids we have to address these issues.
It has even been a topic on gun web sites as they used to use the fluid to treat weapons. But today they found some fluids absorbed moisture and were damaging weapons.
It took Mobil three fluids till they found one to resolve the issue. It is also made to recover a glazed converter clutch. But in some cases the glaze may be too much and a few have had to have the converter changed.
The way MFGs word things is to protect themselves from legal actions that may not always be legitimate.
Many class action suits will take a mfg to court just looking for a settlement. They know the MFGs could win the case but it is cheaper to settle with the law firm. They then take the majority of the settlement for their own reward and offer owners a token prize.
We have a major flaw in our legal system where the looser is not required to pay the cost of the case. So people just due to get paid to go
away as companies can not recoup the cost.
Good to hear how your rough shifting improved. This is heartening news.
Fluid change doesn’t work. GM won’t replace converters, because that doesn’t work either, according to their directive.I have one. I have been buying GM trucks since 1990, with no problems. After this BS, I am done with them.
Which revision of 18-NA-355 was followed and which fluid was used? It matters.
I have two revisions; #16-NA-019 (Nov. 13, 2019) #99-04-20-002K (Oct. 29, 2019) The dealer will be trying these next week.
I had my fluid changed and it didn’t help at all. I could not get the dealer nor the factory to change out the torque converter.
Which revision of 18-NA-355 was followed and which fluid was used? It matters.
#16-NA-361 Document ID:4605342 The latest fluid was used
i complained about this in 2019 and the dealer said yep that’s how they run nothing you can do about it. I found out this TSB was issued in July of -19 and no one told me about it – how are we supposed to know they have a fix. I brought my car to the dealer since then and they were silent about it. Today i brought it in and mentioned the shake was worse than ever and the guy causally says did they change the transmission fluid? I’m like what? unreal – poor customer service at all levels. They should have contacted me a year+ ago and said hey we have a fix for that problem you complained about. They tech said oh we are told to only do it if the customer complains. I said well i did complain over a year ago and you said nothing to do? He said well the fix wasn’t out then. Man what a lame company. I’ll find out if the fluid changes helps or not and if not it sounds like i’ll have to wrestle them for a new torque converter. After they fix this we’ll see what they can do about the Air Conditioner 🙁
Not true the fluid flush is temporary and now GM is not authorizing torque converter changes because that’s also temporary. The lawsuit will go through plain and simple
I have had my 2017 Escalade in for this issue several times. One of the techs dismissed as an “just is” as his pickup had the same issue. Subsequently, they test drove it at my insistence and pretended that the condition could not be replicated and it was in my head. On my last visit, my dealer (Schepel Cadillac in Merrillville, IN) first tried to charge me to for the 50,000 service on the transmission fluid which I declined. They then called me and told me that there was a service bulletin to change it and they changed it for no charge. I can tell you that this did NOTHING to fix the issue. This is BS… I was just looking at buying the 2019 Z06 Corvette as it will be the last rear wheel drive version and now I’m reconsidering that as the same issue affects this model as well. I bought my vehicle certified with 6,000 miles on it and have lots of warranty left. I don’t recall joining any class action lawsuit. Is it too late? Don’t get me wrong – on these class action lawsuits the only people who win financially are the attorneys, but would like to be part of the lawsuit if possible. Thank you for listening and for any advice you would offer me.
This is just so freakin’ wrong of GM.
I guess I have been lucky my trans has been a dream. I would love access to TSBs all in one place as I do have a fuel pressure problem and I don’t want to throw money at it by just changing parts.
This sounds like the same Corporate-speak trick GM pulled with the severe timing-chain stretch issue on all the 2009 3.6 V-6 DOHC Engines every vehicle built on the Lambda platform had. If your engine’s timing chain failed and took out the interference valve train during the original warranty period they replaced it and installed a new timing chain with a different part number proving they knew about the problem. Rather than recall all the four-wheel hand grenades they had sold to customers, they issued an extended engine warranty which still left the owner holding the bag once the vehicle exceeded 100K miles.
So, not a manufacturing defect, but a design defect? Don’t think your making good chicken salad with that argument……..still smells like chicken poop!
GM still made it so they should fix it
GM replaced our 2015 Vette’s torque converter due to engine RPMs fluctuating about 300 at steady highway speed. Then that converter started to shuttle so the dealer replaced the fluid, which corrected it.
Regarding class action lawsuits, even though they make the law firms a lot of money and very little goes to plaintiffs, hopefully they help get legitimate complaints corrected. Unfortunately, it costs a lot of money to defend a suit even if not guilty but if a case goes before a jury it costs a lot more… and you might lose the case and a lot more money.
Well, I had no idea law firms were so altruistic.
My 2017 Colorado had a very hard shift…took it in for a couple reprogrammings of the transmission module and the last one finally seemed to get rid of the majority of the hard shifting. But now I have the shudder (started around 60K), and will be taking the truck in next week…hopefully for the fluid swap.
My question is…even if this would fix it, has all of this damaged the transmission in anyway?
Same issues here on my 2016 CT6 2.0 42k miles. Several service visits… Torque converter problems, hard shifts, shuddering and NOW a code PO711 transmission temperature sensor harness thing? My three prior vehicles were foreign makes up to 100,000 miles and not one single issue period. I’m afraid my Cadillac is crap.
2015 Sierra 92k miles. Mine started making a rattle when shifting from V8 to V4. Not much gas given and rattles. Slow fast it doesn’t matter.. Took mine into Gmc dealer shop today. Hoping its not terrible news. Just paid it off 🙁
I’m a 51 yr old woman..no mud, and I’m very apt to oil changes etc..Im just sick..
Emoto, just post two thumbs down.
Wonder what is going on with lawsuits probably delayed by Covid 19
I wonder what’s going on with the lawsuit as well. I’m the owner of a 2016 GMC Yukon XL Denali that was just diagnosed with a torque converter issue. It’s barely under warranty at 58,600 since the warranty is only good until 60,000 miles. It’s currently at the dealership and they’re only changing out fluids and resetting the computer. An independent transmission mechanic advised of the issue and they are refusing to do the work under the warranty. I’m shocked. Not even 4 years old, under 60,000 miles and an $85,000 POS vehicle. What’s the right thing to tell the dealership to do? They just want to swap fluids and send me on my way. I refused to pick it up today because this is a known GM defect and they’re trying to bandaid an issue to push me out of my warranty. Help!
Dido.
I have the same problem as you.
I have a 2018 GMC 1500 with 18000 miles.
Turned it over to lawyers who specialize in this.
Consumer Legal Services
I have a 2018 GMC Sierra SLT Premium had problems since about 50,000 miles, cared to shop at 59,000 miles now at 62,000 miles and shop three times. They say it needs a torque conveter but they have no transmission fluid for this dumbass truck anywhere in the US to replace the torque converter. This goes deep, i am a mechanical engineer and if you have to have speical fluid developed for your transmission after the fact says you have a problem GM you need to fix all these peoples trucks or buy them all back. Period
I have a canyon 2017 with the shudder problem, i will go to the dealer tomorrow with a copy of the bulletin.
I took my 2017 Colorado in for the second time since I have had it first time talking to a service representative they stated that the problem was from factory putting in bad trans fluid when built. Truck has been at dealership for going on three weeks they are trying to say that vibration is coming from tires. Took it for a drive recorded it at 55 like the stated where the vibration is, the steering wheel is so steady that I could put a drink on it and it won’t fall off. I have contacted GM’s CEO and they are trying to give me the run-around too.
I just posted last week. They are out of the special new transmission fluid all over the US. They told me my truck would be at the dealership indefinitely until they got more fluid in. P.S. they have no idea when they are going to get any in.
I contacted the general manager of my dealership and GM corporate office. They paid my truck off and sold me a new one at the price i paid for my tuck in 2018. They know the 8 speed transmissions were garbage. Stay on them they will make you a deal.
2015 silverado…had to have the transmission replaced at less than 100k miles..metal all over when they pulled it..there were several other similar or newer trucks at this dealership for same reason..not included in warranty they said! $6k i had to spend on a $45k truck with 100k miles..and all i do is drive on highway back/forth to work. I cannot find any doc from GM that says “dont leave 4wd in auto”… Very disappointed in this truck– had to replace a/c condenser and transmission and have front end work.. nothing in warranty..ive had GM trucks for 30yrs and drove them all to 250k miles and never spent money on them like i have this truck..zero response from GM on this…
Same problem!! What is everyone doing about this? Please help! I have taken my truck in so many times. They keep flushing it and replacing little things but refuse to replace the transmission
Turned it over to lawyers, lemon auto.
So far GM will pay $2750 each to owner and lawyer
What about the older cars like the 2012 Camaro I had to change torque converter in 2016 now again in 2020. Why are these not included no where in this.
That is a different transmission altogether. The Camaro had 2 different 6 speed autos, depending on whether you have the V6 or the V8.
Had the shutter problem for ya few years. Dealer put in new fluid and that stopped for 1 year. 2 days ago started hard shifting and tonight it hard shifted and won’t get out of first. Any idea how to get involved with lawsuit or get GM to pay for the fix as pretty sure transmission is a goner.
Good Luck everyone. Took mine in for the 3rd time yesterday.
My truck is a 2015 Sierra Denali, 6.2l with the 8-Speed. The first time the shudder presented itself was at around 22k miles. They changed the fluid per the 1st TSB, and the shudder went away. Then, at around 47k miles, the shudder came again. This time there was a “new” fluid that was supposed to be “the fix.” Now my truck has 61k miles, and it’s back in for the shudder again. The service rep told me that since it is out of original warranty, the bill is all mine now, even though the truck has been in the shop twice for this exact reason. I actually purchased an extended warranty (through Ally, GM’s warranty arm) when I bought the truck, but guess what – it doesn’t cover fluids! There is also a deductible, and diagnostic fees that must be covered as well. The service manager called me today to let me know that I’ll be without my truck until they get a new Torque Converter in and install it, pretty much a minimum of 4 days. At least the Extended warranty will cover the torque converter and stuff, but I have no vehicle for almost a week (today is Friday).
This experience has greatly soured my view of GM. In my 27 years of being on the road, I have had all GM or GM controlled (had some Isuzu’s) vehicles with the exception of one Kia. I have had nothing but reliable, pleasant ownership experiences from all of them. The principle of the band-aid fluid change to get you past warranty is enough for me to abandon GM Light Duty Trucks for….maybe forever. The 8-Speed is bad. I’m abhorred by the fact that GM is STILL using it as the base transmission in everything, knowing of the widespread problems. Caddy’s Camaro’s, Vettes, trucks – they all get it. They seriously could have just said that the transmission must be flushed every 20k miles and I would get over it – but that is not case.
I hear the 10-speed is fantastic, but I expect I will never own one now. I will most likely be trading in my beautiful Denali on a RAM 1500 Limited (can’t believe I’m saying that), a Tundra, or a diesel (2500) in the very near future. I looked at the current F-150, but the seats were uncomfortable, in my opinion anyway.
1500 GMC Sierra…. Serviced my vehicle at the GMC dealership in Arkansas for 100k service in preparation for a Covid funeral in North Carolina. During my trip back, the transmission gave up the ghost in Lebanon, Tennesse. $5200.00 to replace the unit. GM offered 1200.00 to help pay the cost. Thou I appreciate it. Should have to replace a tranny in a vehicle little driven.
How did gm send you money did you get lawyer if so please give info
Ok so I know this seems to be specific to the 8speed but my Colorado is a 2016 and it has been miserable since day one. I was told it needed to break in. Then it needed a fluid service. Then another. It goes on and on. I’ve changed the tcm, applied the most recent tsb, more and more. It’s got 65k miles and I have to MASH on it to get to 70 and then it takes off rendering me single digit fuel economy. In a mid size truck. Im going to service it one last time and then im buy a dodge.
Have a 2016 z51 Stingray that I bought CPO in July of 2019. Now having the issue with shudder and hard shifts at low speed. Just starting with my dealer and of course they are saying there is no TSB for my vin….My ride is a pre 2019 build, clearly and I have the original build sheets, so I know its an M5U tranny. Wish me luck I guess!
Bryner Chevrolet in PA took care of me with no issue and got it covered.
Stick to your guns and demand the fluid flush. So far it seems to have resolved the issue!
Gm is a joke. I bought a new 2019 colorado and had the shutter on the drive home from the dealer. Dan Tobin in columbus ohio is where is was bought and repaired. First time in the shop they changed the uid to the new fluid. That lasted for a few months . Second time they did the same thing. That lasted for just a little bit also. The third time I requested a new transmission and they refused and installed a new torque converter. This also didn’t last long and they found lots of metal shavings in the pan. They replaced the transmission and I lost several miles per gallon and it still has a shutter.
My 2015 GMC AT4 has had hard shifting since new. It’s been to the dealership multiple times. The dealer reflashes the transmission and says it’s good to go. I am actually sitting in the dealership right now because the transmission is causing the check engine light to come on. This transmission is a disaster and GM refuses to acknowledge it for economic reasons.
Can someone refer me to a lawyer that is handeling this problem for transmission please thank you
Lemon Law Office.
You need to have taken your vehicle in four times to a dealer for a transmission problem before you can file.
2015 GMC Sierra SLT .Bought truck used in 2018 with 55000 miles. noticed very slight shudder,seemed to be a tire issue. replaced all 4 tires with no change but shudder was so slight and would only happen occasionally .now with 85000 miles truck shudders unless you keep it in manual7 th gear,trans temp is high now also.dealer says needs new fluid and or torque converter.
2019 Sierra SLE new gen. My 5th visit with the dealer already. They had the tranny fluid replaced already – no change.
Now they’re replacing the TC and will have the tranny and coolant flushed.
Now a million dollar question: After replacing the TC for the 2019s, did the same problem ever came back?
I did some research – no luck finding anything for the 2019s.
Absolute BS. Came back to GM buying a Cadillac CT6 and this is what I get?? Garbage transmission flaw and GM will not fix it??
The fluid swap is not fixing the issue and neither is a new 8speed transmission. GM needs to swap out the transmission all together. What a joke of a company. Looks like it’s time to start buying foreign as the quality of US vehicles and dealerships has declined to junk!!!!
Interesting fact. They did end up fixing it for me after 5 visits and being a pain in the ass.
*Tranny Flush – no change
*They had the body valve replaced – no change.
*TC replaced – Feels ‘better’ but the issue is still there.
Then they had the camshaft sensor disabled – issues GONE.
It WASN’T a faulty camshaft sensor itself.. they ended up replacing the actuator.
Been driving it for 2 weeks now with no issues.
Does anyone know the best way to contact GM and register a complaint!?
I have a 215 sierra denalli and I had my transmission flushed less thene 20 miles ago and now same shimmy and ruff shifting called dealer ship after was told they would half to change torque converter if did it again and now they tell me that I half to come pay 450 dollar plus tax to get flushed again don’t think its right of gmc to due these when they know they ha e a problem with these transmission
I have read many of the comments and I have questions. Automatic transmissions have been around for several decades. The basic technology is nothing new. So please inform as to how GM engineering can so screw up a transmission ? Do not they not pay attention as to what they are doing? Do not even begin to think through the design? Geez its an automatic transmission but they cannot design one that is reliable? They end up putting their customers through all this aggravation ending up with very dissatisfied ones that may never buy or lease another GM product. I am a 2xs Saturn owner and I can remember reading the Saturn fans website. While I cannot remember the exact name of the website what I clearly remember is the transmission debacle regarding the Saturn Vue. It seems that there was an extraordinary amount of transmission issues and failures with the CVT transmission used in the first generation Vue. I read complaint after complaint , problem after problem and how many disgusted Saturn Vue owners would not only never buy another Saturn or any other GM vehicle. Some owners were repeat buyers. I believe that this was a major reason for Saturn’s decline as being seen as a reliable brand. GM did not learn from this and it seems that to this day they still do not realize or care that a dissatisfied customer remains one. I do not care one whit what corporate bilge GM spits out about these 8 speed transmissions. They did not learn from Saturn and it certainly seems that the “new” GM is the same as the old GM. These problems should not be happening. GM owners should not have to deal with this and are entitled to reliable vehicles. Excuses are just that excuses and a poor reason for not paying attention to what they are doing. An 8 speed automatic transmission is not the same as developing warp drive. If we can sent men to the moon & back GM can certainly design a reliable transmission
I have the 2018 GMC Sierra with a recurring trans issue. I have had it in the shop 5 times. The first and second times I was told they couldn’t replicate the hard shift. The third time I was handed a 9 page service bulletin and was told that it is “expected behavior” for this trans to slam from first gear into second and to shudder. On my fourth visit I mentioned the Mobil 1 trans fluid change that I had read about on this forum. They changed the trans fluid and that seemed to help the shudder but not the hard shift issue. On my fifth visit I was told that they would re-flash/reprogram the trans so that the shift points are different. I was also told that it would take a few thousand miles before the new programming took full effect. I now get 10 mpg where before the reprogramming I was getting almost 17 mpg. I also still have the hard shift and tons of slippage between all gears. I can not confidently slow down and hit the gas to pull into traffic, for instance when making a right hand turn, without the engine racing to 5K rpm before the trans finally catches. This is the biggest lemon I have ever owned and this trans issue is only the tip of the iceberg when it comes to issues that I have had with this truck. I have been a lifelong GM customer going back to the 80’s. I would never recommend anyone purchase a GM vehicle of any kind. Needless to say, I will be taking it back in again this week. I would love to sell or trade this POS in. Unfortunately, with the way it drives, I would never get full value.
Is GM paying anything toward this repair or do the owners have to foot the bill?
GM covers everything while its still on warranty. Though they’ll march you through hell before getting it fixed (if at all).
I don’t see how GM can stay afloat. Maybe they’re just going to go electric and try to forget they ever put these worthless transmissions in their cars?
I have a 2017 Yucon Denali with a trans shudder. The fluid has been flushed twice with no improvement. The dealer has had the Yucon for four weeks and they have yet to say what they plan to do to fix it. I have lost faith in GM.
They’ll say it’s working as designed and do nothing. Garbage Motors has zero backing of their vehicles.
My trans was diagnosed DOA today at the dealer. Hard shifting lead to it falling apart. Sign me up for the lawsuit. I’ll need some $$$ to cover the trans replacement. 145k highway miles is all she could handle.
2015 silverado 2500hd 6l90 changed fuild and still converter and pump failed! Think transmission engineers could figure it out!
Finally was able to get the issue in my Cadillac addresses. Took 6 trips and this service advisor actually took the time to write down everything and the service guys knocked it out. They replaced the torque converter and valve cover. Valve cover was causing the shutter and the torque converter was causing the insanely hard 1-2 shift. Couple weeks now and the car is finally perfect!
I have 2018 Sierra Transmission flush had been completed did not fix the issues of hard shift’s,shutter etc.the dealer gave me a paper stating that this is normal this is not normal at all it will end of failing someone is pulling my chain period.
I just traded in my POS GMC Sierra and took a bath on it. I could not sell it to a private party because of how bad the transmission was shifting among all of the other problems. I lost around $10K by trading it in (I received $37K instead of KBB private party average of $48K) instead of selling it outright. I complained to GM numerous times about diminishing values and returns. They don’t care. They keep going back to it being an engineering defect and that those are not covered under warranty. GM is the worst company I have ever dealt with. I highly recommend everyone avoid them. I replaced it with a new RAM and so far I am happy I did (6 weeks of ownership).