As we’ve covered several times in the past, General Motors is facing several lawsuits over alleged defects in its eight-speed automatic transmission, which has been known to exhibit various drivability issues, including, shaking, jerking, and hard shifts. Now, new information provides an important data point in the GM transmission kerfuffle.
Based on court documents seen by GM Authority, GM may have been aware of the issues associated with its 8-speed transmission as far back as September of 2014. The documents cite a number of technical service bulletins (TSB) and other GM communications about issues associated with the 8-speed transmissions in question. Coincidentally, September 2014 was roughly the time that GM launched the eight-speed gearbox.
GM 8L45 automatic eight-speed transmission
Besides the pending class-action suits, a variety of issues associated with eight-speed GM transmission have been documented through complaints filed with the National Highway Traffic Safety Administration (NHTSA), thus demonstrating the widespread nature of the issues.
The gearboxes in question are the 8L90 and 8L45 eight-speed automatic transmissions installed in a wide variety of rear-drive-based GM vehicles spanning the Chevrolet, GMC, and Cadillac brands. Vehicles specifically impacted include:
- 2015-2019 Chevrolet Silverado
- 2017-2019 Chevrolet Colorado
- 2015-2019 Chevrolet Corvette
- 2016-2019 Chevrolet Camaro
- 2015-2017 Cadillac Escalade and Escalade ESV
- 2016-2019 Cadillac ATS and ATS-V
- 2016-2019 Cadillac CTS and CTS-V
- 2016-2019 Cadillac CT6
- 2015-2019 GMC Sierra
- 2015-2019 GMC Yukon and Yukon XL
- 2017-2019 GMC Canyon
More than a dozen technical service bulletins (TSBs) seeking to remedy the GM transmission issues have been issued thus far. In August, we reported on the new 18-NA-355 TSB, which apparently fixes the issue via a special type of Mobil 1 automatic transmission fluid.
2019 Cadillac CTS
Specifically, the 18-NA-355 TSB addresses “torque converter clutch (TCC) shudder conditions” for the 8L45 and 8L90 eight-speed automatic transmission, RPO codes M5N, M5T, M5U and M5X. The issues appear to stem from moisture in the transmission fluid. In fact, some GM Authority readers have written in to tell us that the transmission flush using the Mobil 1 blue fluid via the 18-NA-355 TSB fixed the issues they were previously experiencing.
However, if the fluid swap doesn’t fix the issue, the next step may be a replacement torque converter, as a vehicle’s existing torque converter could have become glazed.
We’ll follow this story as we discover more, so make sure to subscribe to GM Authority for more GM recall news and 24/7 GM news coverage.
Comments
My fluid was changed to the latest and greatest on my 2018 GMC Sierra, not the remedy.
Did they replace your torque converter? The damage may have already been done.
They are now under orders from GM not to replace them.
I have a 2016 Cadillac CTS and I changed the fluid two weeks ago and the shuddering has stopped.
3 of us at work have had the latest flush and all is well.
Might note I have seen where some dealers are doing the flush to spec too. Make sure they replace 20 quarts.
Don’t forget C8.R is scott3,
And he had his entire transmission replaced !!!!
So did the fluid flush work for him ?
Well maybe on the second transmission !!!!
Deception, at its greatest !!
In my opinion !!
My 2016 SS Camaro started shudder at 11,000 mi. Dealer did flush. Seemed to fix. Nope! Took back dealer did new flush at 19000 mi in 2018. In April 2019, hard shift rear end shudder began again at 24000 mi. Dealer had no solution. I sold my Camaro to Carvana. June 2019. My heart and joy broken as I worked so hard to afford this amazing car. Dealer promised once a fix was determined a recall would be given by GM. I had no joy driving my Camaro.
What’s the dealer promise worth(absolutely nothing)…G.M. is not going to recall these,they are going to run the clock out..What’s mind boggling is G.M. engineers designed this transmission BUT they can’t fix it?My 2017 Cadillac ATS Premium luxury has had the fast learn done,the fluid swap done BUT it went back the same.I have spoken to Cadillac Ambassadors numerous times and heard the same thing(once a fix is determined I would be notified.Guess what? I have not heard from them…surprise surprise…And at this point I don’t give a shit.I have drove this vehicle over 3 years now with this problem so all it would be doing is possibly fixing it for someone who buys it used /not the person (me) who bought it new for $56,445.00.G.M is not going to fool me again.
While the fluid was flushed and did remove the shudder. The Yukon still experiences hard shifts in second and sometimes clunking noises. The vehicle has been in for service more than several times with more than 200 miles put on it during a single service. At this point it is just something to expect and live with. I would think a customer would deserve better if someone spend well over 70k on a vehicle.
I had the hard shifts and clunking noise on my ’15 Corvette. It was fixed with a software update for the transmission control module.
Not good news for GM is true
Yep,
GM is just buying time again !!
That’s what they do best !!
If they wait long enough, they push more out of warranty, and let the customer join the class action lawsuit where the lawyers get rich and the customer just gets screwed longer !!
We have seen GM do this for years now, nothing new !!
In my opinion
It’s not just GM. You’re describing a common problem with a creation called a for-profit corporation.
My Mercedes-Benz SL AMG was part of two class action lawsuits… one of which has been ongoing for almost a decade. Mind you, this is a $130,000 car (when new) that can’t deliver proper windshield wiper performance, with one or both wipers always shuttering against the glass. This is also a car that at 13,000 very easy miles needed a complete suspension overhaul.
My friend’s Volkswagen was part of a class action lawsuit regarding infotainment features. Oh right, and the Audi A4 that I had before was also part of a class action surrounding premature suspension failures. And let’s not forget about every single German automaker being sued by various governments AND by owners for cheating emissions tests.
Until humans come up with a better entity than a for-profit corporation that can make cars and make everybody happy all the time, this is the reality. GM is part of that reality. So is Ford. So is VW. So is Mercedes… and every other automaker. Let’s not let fiction get in the way of reality.
Alex,
You are correct, its the reality of C a p I t a l I s m.
And thank you for saying all brands are the same and GM is no better !
It’s not a race to the bottom though…Reminds me of grade 3..”Well Bobby and Billy and David did it too”…In my instance a 2017 Cadillac ATS Premium Luxury($57,000.00 Canadian) its not acceptable for G.M.’s Premium Brand to have a major drivetrain malfunction(8 speed transmission).Cadillac is trying to re-brand..not the way to do it..The transfer case also has a whine starting at around 39 mph..G.M. issued a bulletin stating this is normal…IT”S NOT NORMAL”…Wasn’t normal on my 2013 Cadillac ATS AWD because there was no noise in it..
That’s where GM is at now though,
” GM the cheap brand and racing to the bottom of customer support !! ”
This is the deal on this transmission problem, well a lot of the GM class action problems !!
There are not more lawsuits against GM do to they sell more vehicles in the USA, there are more lawsuits against GM do to horrible customer support !!
The lawsuits are only on the ” known faulty ” parts of GM !!
Not on the high volume vehicles !
They are trying to tell their long term loyal customer how a transmission is to feel.
Why cant they see these customers have been driving vehicles for years and that the majority of their, GM, transmissions don’t do this !!
In my opinion
Class actions are not a rarity in the auto industry or honest lawsuits.
Most class actions are for profit lawyers who take most of the money they get in a settlement because they know they can extort the money from the companies.
The one thing more greedy than a for profit company is a Class action lawyer,
C8.R,
You are also correct, lawyers are just profiting from people who have no where else to turn !
Greedy, lawyers, and that’s why I would never join a class action lawsuit, no matter what !
I had the fluid flushed on my 2019 Chevy ZR2 Colorado and it did fix the shudder issue but I’m still dealing with hard shifts.
I’ve had the fluid change but had to pay out of pocket. Not a happy Chevy owner! I’m embarrassed to have anyone ride with me.
How can I recoup the money, time, and aggravation?
I had the fluid change on my 16’ Sierra Denali. It still shifts terribly. It is not fun to drive. It’s like the transmission has no idea what gear to put it in.
I am in a 2020 Silverado 1500 with 1000 miles on it. There is a slight shudder when downshifting out fo 8th, cruising at 55 pulling a slight grade. It is a beautiful truck, but I would not buy any GM product with this transmission.
I have 2016 Gmc Canyon 2.8L diesel. Had shifting issueand shuddering. After 61k miles. Had to pay out of pocket. For GM dealer to flush. That didn’t solve the problem. Took it back replaced torque converter and flushed again. Temporary fixed the issue. 10k miles later I’m starting to feel slight shudder again??!!
Mike you have a Six speed not the 8 speed they do have a TSB on them and it was not a fluid issue.
My 2019 Vette is stating to act up! When all the problems 2020 Vette start to show up G M will be kissing ass to fix them then a few years they will just kick them under the bus like they have to us! How and the hell did G M become such bottom feeders!?
My 5th Cadillac in 20 years! and I can say ”they are not getting better” . The transmission rough shifting reminds me the first time, at age 12, when I drove a car with standard gear box.
Which model do you have, Marcel?
That’s the truth Marcel Bernier !
My fifth Cadillac a 2014 ATS, bought so I would not have the 8 speed junk !
But it still has no idea how to shift gears, or what gear to be in !
My 2015 Canyon WAS the same, again the 6 speed for the above reason, did not want the 8 speed junk !
Bought a tune for the Canyon, it now shifts great, and I get three mile per gallon better mileage !
Good luck with GM customer support !
You say you bought a tune? What did you do specifically? I’m in the same situation.
Grayco,
The GM game with the 6 speed transmission is the same game GM plays with all products !
Mine started out at 2000 miles, 6 speed 3.6 Canyon All Terrain. The upshift is so quick that the 3.6 simply has no torque at 1100 – 1200 RPM. When this happens the engine pings, jumps, shutters, etc. So at this point the customer tries to accelerate, when the customer does, you need over half the travel of the pedal, then WOW it downshifts to the top RPM of the lower gear. You still go nowhere because your at the top end of the lower gear.
As scott3 or now known as C8.R, pointed out, GM has a TSB to address this very thing, of course its 3 years out as to ” push most customers out of warranty ” so GM doesn’t have to pay for the fix of a ” known faulty ” issue.
So with the 6 speed there is about 500 to 700 dead RPM to deal with in the 3.6, it simply has no torque at 1200 to 1700 or so, that’s why the 2.8T diesel still uses the 6 speed !!
So I bought a tune from Trifecta, there are many out there, for everything stock, just want the transmission to shift ” correctly ”
Downloaded the tune to a laptop, they sent me a cable for the ODBII connector and done !
It shifts like it should have from GM. Holds the lower gears to around the 2000 RPM range as to keep some torque !!!
I am assuming, by holding the gear to the 2000 RPM range it prevents the MASSIVE RPM DOWNSHIFT and therefore has increased my mileage !!!
When your on the road just turn on your cruse and it reverts to factory and I get 28 to 29 MPG, when you get close to a town or city, shut off the cruse and its great !!
And one more time, if GM had any customer support, they would have done this for anyone who stopped down to the dealer and asked about it ” for free ” !!!!
They did not have to do a full on recall, just deal with their ” known faulty ” stuff !!!
If I had the time and the money I would can the 6L80 in my Yukon and put in a manual transmission. I wish GM still offered one. My ’98 K1500 has over 300k miles. I’ve replaced a clutch and throwout bearing ONCE! No other problems. The Yukon has had one new transmission and the second one rebuilt and only 160k miles.
How do you go from building some of the best transmissions in the world to building some of the worst transmission.? There was a time when some of the finest vehicles used GM Transmission because the wer the best out there. I guess it goes with the territory I remember when GM was once considered one of the best auto company’s. Not so muc anymore.
2016 Sierra 6.2/8L90. Started getting the “shudder” at 95k miles. Took 2 months to get in for service because the dealerships were on quotas for the special fluid required. Flush + new fluid fixed the shudder, but then I started getting crazy shifts ($500+). Took it back to dealer and they said the wiring harness tested bad and replaced it ($1,500) along with an even newer fluid update. Was “okay” during the relearning period, but has gotten progressively worse since. 1-2 shift is crazy hard and, sometimes, includes 500+ RPM of slip. 2-3 is funky, and 6-7-8 are occasionally weird. A downshift that occurs at about 25mph always comes with a hard clunk. Huge POS. Will probably cause me to buy something other than GM next go around, for the first time ever.
Wow. 185,000 miles on my 2011 Tahoe, never changed fluid just now starting to experience it not downshifting when slowing down but hey 185,000 miles. I am holding out for the new Tahoe in 2021. I hope buying a first year run isnt going to bite me in the A**. It will have the 10 speed transmission…crossing my finger as i love my Tahoes
GM is building Junk under Steve Carlise. I wish the Company still had Bob Lutz and Johan as part of Cadillac to give management a tight slap for approving laughably bad vehicles like the XT6.
expensive repairs but its time to step up to the plate ,if the penny pinchers choose the cheaper way for these parts and Mary agreed to that let her pay out of her obscene salary
I had the flush also. Problem came back, now it’s worse!
2018 ATS Luxury
I got a 2014 Silverado 4.3 hard 2/3 down shift an a jumping up up shift the fluid temp is normal at 190 an level is correct on point at operating temperature why cant g.m get a transmission rite these days smh!!!
This is a sorry state for a company that was known and respected for its great transmission around the world. So much so that some of the finest automobiles in the world used their transmissions.
Heck they were the first Auto company to offer automatic transmission in production cars. They also once owned Allison transmission..
Now it seems that they cant produce a good transmission to save their lives. Makes you wonder if its the lack of capability or just because the are trying to do everything on the cheap.
My 2017 Chevy high country with 23000 miles on it has been to the shop 3 times now. I had the tranny flushed and have the mobil 1 synthetic in now. The shifting is STILL hard from 1-2 and on the down shift 2-1. I have owned nothing but Chevy. I’m currently looking for a Ram 1500. I’m done with Chevy. I have been getting the run around like everyone else. It’s pretty sad that my 92 Silverado shifts smoother that my “high end” 2017 high country. Worst investment I have ever made. It’s too bad it will be someone else’s problem. The sooner I get rid of it the better.
After 4 repair attempts and $2,000 spent, three months ago I had the dealer replace my 8L90 with a GM unit. $4,500. 3 years/100k warranty. This weekend I got a check engine light. Ran the codes…transmission issues. Called the dealer, gave them the details. In 5 minutes they called back and said “My transmission guy knows exactly what it is. We’ll order the part and let you know when they’re here. Probably 2 days down time.” GM should be embarrassed by this POS transmission.
I bought a brand new 2017 Colorado. Got the shudders after about 6 months, first time I took it in they told me it was normal and “the Colorado has been redesigned for optimum performance blah blah blah”. I left confused. After a few weeks of extensive research, I found the TSB, and had the dealer perform the transmission flush. Everything seemed fine, until a year later. The shudder came back, and I had to wait 3 months for the new fancy Mobil 1 ATF. Flush was performed, and everything seemed fine. However, now I’m dealing with the hard shift between 1/2 and 2/1, not to mention the other weird quirks that this transmission has always had, like not knowing what gear to be in, and then there’s the weird throttle delay. If you pull out into traffic, you better be prepared for that one… your throttle sometimes has this weird delay and the truck will just kinda stall and sit there before the transmission starts to pull.
GM, I’m done. I gave you a chance, and you blew it. Never again. This truck is GARBAGE.
Been there, done that, got the receipts to prove it. I believe there’s secondary damage occurring while the transmission is “shuddering” as you wait your turn to get the latest and greatest fluid. Maybe some debris coming from the torque converter clutch material that eventually clogs or wears on other parts. Nothing $4,500 or a trip to another brand won’t cure.
Just had the trans fluid changed on my 2019 Vette Grand Sport (warranty of coarse) 3 stage flush equals 24 liters of fluid at a list price of $43.95 Canadian $$.s plus several hrs labor!
I’ve been done with GM since 2010 . I went with Ford in 2010 and with a 07 xl with 265,000 miles on it I trust more than I would with any GM vehicle. GM is junk and only one I’ll ever own again is my dads 69 step side
I bought a 2016 Chevy Silverado I have 81000 miles on it and had to replace the transmission and transfer case already very disappointed in GMC thinking of buying of buying a FORD myself they known about this problem TWO YEARS prior to me buying my Chevrolet I bought a new truck so I didn’t have to work on it 3 years later it cost me $4500
2014 SUBURBAN LT DECEMBER 2019 MY TRANSMISSION FAIL ON THE ROAD WITH NO REASON I TOWED TO AMMCO THE OIL WAS GOOD BUT THE 6 SPEED TRANY FAILS I END UP WITH A $3700 DOLLARS BILL, THE MECHANICH TOLD ME THAT CHEVY KNEW ALL ABOUT IT BUT REFUSE TO RECALL
I’m fed up with this piece of crap transmission!!!!! Tonight we were leaving a parking garage and my 2016 Cadillac CT6 3.0tt has proven that this is an expensive waste of money! I was rolling waiting in line with other cars in fornt of me and as it went into 2nd gear without even hitting the gas, it slammed like it had a shift kit in it! Complete F***ing disgrace! My wife yelled ‘What the hell was that!’. SOMETHING HAS TO BE DONE! My dealer is getting a call monday morning. I already had the Mobil transmission fluid flush a few months ago. GM is gonna start to hear me roar!!!
Been there got the T/shirt…2017 Cadillac ATS Premium Luxury 3.6 AWD ,Fast Learn performed.. Fluid swap performed.. Fought with Cadillac Care for 3 years…Finally I had to trade the vehicle and I make aware on social media that General Motors will not honor their warranty commitments.They will NOT fix them… In good faith I hate to see another consumer go through the expense and grief I went through and you are going through!
Do not let up on those Generous motors Pricks!!!!!!!!!!!!!!
I worked for GM for almost 32 years in Reliability Department and was very dedicated to them when purchasing a new vehicle. I have a 2014 silverado and having transmission problems. Need a reliable truck to pull our 22’ Forestriver Wolf Pup travel trail.Trailer weight is 3900lbs. This is way more truck than is needed. This is a known issue with these transmissions. If GM does not make this right with me I will take my purchases and all my families purchases to another company. My sister just used my GM discount to purchases 2021 Silverado not 6 weeks ago. I do not do business with companies that do not back the product.
My 2015 Silverado truck just had a transmission failure/slipping at 125k miles. The dealer has had my truck now for 9 days. The quoted me a new transmission with 3year/100k warranty for $5177 installed. This is 1/2 what I owe on my truck and chevrolet is not willing to do anything because it is out of the original mfg warranty.
My family and I will not be buying another GM/Chevrolet product again.
My 2014 Silverado has a bad transmission. Rumble strips indeed. I bought it in 2019 and the warranty has expired. I shouldn’t have to pay for this defect. 🙁
A friend had this problem with a 2015 Vette and was fixed by changing and flushing the trans fluid it was around $ 1,300 at a GM dealer. This is in Canada!
We have 3 of the 6L80 Transmissions in Our household. 2014 silverado, failed at 127,000 miles. A 2015 Tahoe that failed at 120,000 miles. And My 2017 Silverado that failed at 78,000 miles. It is truly pathetic that GM is not standing behind this and I hope there will be a class action lawsuit against them.
Are there any lawsuits for the 6 speed transmission in 2015 Silverado with same shudder problems?
COME ON! I’m a Chevy man born and raised. I purchased my 2017 Silverado k2500 in 2018 with 15000 miles on it 6.0 .4wd to pull a travel trailer. For a retirement dream that my wife and I have had for years. I’ve always questioned the trucks performance pulling our camper? shifting was terrible I’ve always thought something was wrong! 64,000 miles now and a 5,000.00-dollar repair that should have never happen in the first place? 67 now and disappointed in the strength of my born and raised !!