45,000 Miles In I Got Transmission Flush Done To My 2021 Silverado At Dealership, But After Spending $400 It's Worse Than Before

Dealerships, just like any other business have personnel changes. This can effect the proficiency level of the service department. One year they can have multiple techs that are really good with A/C, transmissions, and engine diagnostics. Then for some reason, the good A/C tech and engine diagnostics tech both move on. Now the dealership is advertising for more techs. They aren't telling customers they're currently lacking in those areas.

I remember looking at used cars at a local dealership. Their polishing and buffing guy at the time was not well trained and most of the vehicles on the lot looked horrible in the sun.

Had the same issue with my 2013 Suburban. After the dealer flush and 2000 miles, I started getting the torque converter shudder. Mine has the 6 -speed. I went to a reputable transmission shop who ended up rebuilding my transmission and put in a HD torque converter. He told me that these issues are common with all makes and the 6/8/10 speed transmissions. Very disappointed in American engineering. Never, I repeat, never have a transmission flushed. It is just premeditated failure. Drop the pan, drain, and fill, is all that is needed.

My 2012 Chevy Silverado 1500 rwd with the 6L80e tansmission started hanging between 1 & 2 & 3rd, gear after I had the transmisson flushed and refilled at a local oil change facility in Tyler, Tx. It started the gear missing shifts and the torque converter started humming. The tranny was rebuilt, then we found out auto zone sold us the wrong torque converter. Chevy had 3 different torque converters for the 5.3 engine, you have to go by the v.i.n. to get the right one! I am now on my 3rd try to get a rebuilt one installed. I sure hope it works! I will go back to a GMC Denali 6.2 after this p.o.s debacle!!!!

I have a 2018 GMC 2500 heavy duty. It has a problem with exhaust fumes going in the cab ever since I bought it when it gets into that mode where the exhaust fumes are coming into the cab. It is burning double the fuel after about 30 km. It goes back to normal. I took my truck in when it was under warranty. So many times they told me it was all in my head and it's my fault that it was doing that. This was at the dealership in Chatham, Ontario on the corner of Kyle drive and grand ave. They do not treat you like a customer I. Spent almost $92000 for that truck. All they did was give me the runaround. Even when the service manager that originally was there before installed the goose. Neck assembly in the back of my truck. He did not put it in properly. And the one acre broke when it was hooked up to my trailer. When I turned a corner sharp I had to replace it at my cost. That is not right. They have done a lot of dirty deeds there with me but they never fix my truck. And it still does that today? Burns, double the fuel and you get exhaust fumes when I went on Google, there are thousands of people. They had the same truck as mine with the dura max 3/4 ton. And they all had problems with exhaust coming in the cab. General motors never fix that. And that's not right, and my truck still does that today. I will never buy anything from that dealership again. They should be coming good and fixing my truck like they should have done from day one when it was under warranty

Bought a used 2021 Silverado with the 8 speed transmission. Before purchasing I took it out for a test drive, when I returned, I told the salesman that the gear shifting was not smooth and it shuddered. Vehicle had 68K miles, certified used-warranty good to 100K on Powertrain. After owning for 30 days, I tool it to the dealerships service dept., explained the issue, after an 1-1/2 hours repairs were completed.
Steps completed:
1: Drain transmission fluid
2: Drop the pan and filter
3: Inspect & clean exposed components
4: Install new gasket and filter
5: Refill transmission fluid, check fluid level after warming up the engine
*NOTE*
There is no transmission dipstick, GM eliminated it, transmission now has a fill/check plug located on the upper backside of the transmission. Hard to spot, even harder to get at!
Before any of the above service work was performed, the starting battery was disconnected. According to GM, by performing this procedure (min 30 minutes) it resets the TCM (Transmission Control Module)
You can’t make this stuff up!
BTW, my transmission shifts just fine with no shuttering. 😁

Just get an electric truck. Solved.

Stay away from the Silverado with 8 speed transmission. Period !

$400 is a steal. I just changed the transmission fluid on my 2020 5.3L Trail Boss, and it cost me $800. Mine though actually shifts smoother than it did before. I used a local auto shop that I trust. I know they also took it for a drive after the flush at specified speeds and accelerations per manufacturer spec.

I have had issues similar to the 2019 Silverado’s. Like clunking into and out of gears, missing shifts, etc. However, I own a 2019 F-150 with a 10 speed transmission. I have been told it was a computer problem by 3 different Ford dealerships. They also said after replacing the transmission fluid and “resetting” the computer, that it would take some time for the computer to “adjust” to my “style” of driving. With a “closed” transmission in the 2019 F-150 there is no way for me to check the level or add anything to it. When (2) of the dealerships changed the transmission fluid, each of them said that there were metal shavings in the “old” fluid.? Any guidance or recommendations for extending the life of my
2019 F-150 (it only has 70,000 miles on it) would be much appreciated.

Had new rebuilt from GM put it at 89k.
Changed fluid& filter at 115k,still doesn't know where to shift sometimes,had Chevy all my life,maybe time for a change???

My experience says that you shouldn’t flush the ATF unless the fluid has been damaged by overheating. Despite the best efforts by OEM to remove contamination during gearbox assembly, there is almost always some small amount of debris in the transmission when new. If you’ve driven 45K miles with minimal problems, that debris has found a “safe” place. Draining and flushing stirs it up and it can end up in a valve or clutch and lead to poor shifting. There might be other issues too but again, unless you’ve been pulling a heavy load on a hot day or your transmission oil cooler leaked, changing the ATF is more likely to cause more problems than it might fix.

2019 Newest Generation Silverado 1500 rear wheel drive 5.3. Locked Up 4 Times back to back to back to back times on the interstate in 10MPH traffic jam. Had it towed to dealership thinking it was the breaks locking up. When I bought the truck in 2023 it had 18k miles on it. A year later at 42k miles is when this happened. After having it a month, they still couldn't get it to replicate what had happened. Finally I did some research myself and figured it could have been the transmission the whole time, so I suggested to them they take a look at that issue (I couldn't believe I was asking them this). They said, sorry. There's nothing wrong with it. I said, I'm not taking it, it's a safety issue. Once I brought up "safety" they changed their tune. (Everything was transcripted through text). Finally after another week, they (dealer) said they spoke with GM and said it was a module inside the transmission but it wasn't covered under warranty, bumber to bumber was over, I said "you just told me it's inside the transmission, that's power train warranty. They went from wanting to charge me $1,700 which I said FU, down to you can come pick it up, we fixed it. When I went to pick it up, I said did you flush or change the transmission fluid, the Service Manager, not the desk guy that don't know shit said, it was flushed when we changed the converter, I said why did you change that? He said it was changed with the previous owner, I said "wait, what?" I was told that there were no issues previously with the transmission, he said they musta lied, I said . .y'all all lie here! I took my truck at no charge. I don't think they would have ever looked further into it if I had not made it a safety issue with it locking up 4 times in 25 seconds on the interstate, which a passenger could have hit the windshield or someone rear end me. Since then, I still get the Chevy Shudder at times but the one thing that bothers me the most is when going from Drive, to reverse back to drive ... It will slip then jamb into gear .. not all the time but 50/50 and also the clunking now and then. I just have a feeling this is not the last of it. Now, it's December 24' with 67k miles on it .. Body is in Great, almost like new shape still .. should I sell it? And if I do sell, what to get? I'm a diehard Chevy Guy .. I feel like I was lied to, many times by this dealer. I can't see myself in a foreign truck, and Ford and Ram, not for me. 🤷🏼 I won't name the dealer as of now but it's in Metairie, LA.

After experiencing shuddering on my 2019 Silverado with an 8 speed transmission, it had to be replaced at 80,000 miles at a cost to me of $7500...it was out of warranty ...I am included in a class action suite, if any recourse will be available.

I’m just not a GM fan any more. Last GMC Denali I bought a few years ago was a complete disaster. Had 5-6 GM trucks before this which were generally fine.

I now drive a ford f-150

45K miles for a transmission flush? Sounds kind of way too soon to even think about something like that. I don't know what the owners manual for that specific truck exactly says though. Then to pay a dealership to do that for you (or have them do ANYTHING for that matter, outside of completely covered warranty work or recalls) is just allowing yourself to be gouged. Anything a dealership might recommend to you is likely nothing short of a sales tactic. Most are notorious for telling you that you need to have things done (especially for any kind of state inspection or the like) when you most likely do not. Most have become scammers when it comes to maintenance and repairs of cars. We followed dealership estimates for many many years and they always came in on TWICE as much as any other independent garage that knows what they're doing. We've caught dealerships in lies in the past when getting second opinions elsewhere, which has completely eroded our trust in any dealership anywhere anymore.

Don't do flushes because they end up pushing build up in all he wrong places
Many tiny little holes that once they get jammed up with gunk,van cause problems
Only get drain and refill with the exact amount that came out (measure what came out) only use fluid from the manufacturer
Trust the manufacturer (but never trust the dealerships for anything) 2 very different things
Scotty kilmer is the man

I had same trans that chattered the torque converter. I must be thoroughly flushed ( tranfusion) with Mobil 1 tranny fluid. Chatter gone within 2 miles of driving with trouble free service since.

When we do a flush at the dealer, if the fluid is burnt or otherwise really worn out, we will reset the transmission adapts, this resets all the shift points, pressure, and general operation of the transmission back to factory default. The technician is supposed to go drive the vehicle and get it back to a functional baseline. But if you reset it, and then have a customer with a heavy foot, which everyone has nowadays, it will exacerbate the ard shifts and the like.

The transmission isn't "worse" just different, and customers need to understand there is a learning process for both the driver and the truck.

One thing I will say, is people drive very aggressively, especially with new vehicles. I don't know why that is, but it's not great for the vehicle, just because it has a warranty doesn't mean it's indestructible. People need to test drive vehicles before they buy them. And that includes towing your rig if you have one, because buyers remorse is not a warranty claimable problem.

Here in upstate New York the Capitol Region - Dealer service is appalling - The Chevy dealerships are pretty much all the same - All young inexperienced service techs - No adult supervision in service shops - Going to the dealer for anything after the purchase is always a big mistake - Even complaining to corporate doesn't help - Never used to be like this - Avoid dealer service at all cost - Chances are you're problem isn't the Truck it's the inexperienced young boy mechanics - Good Luck.

You all are probably not going to like this, but buy a Toyota. A friend was a mechanic at our local Toyota dealer for 10 years. In those 10 years he never had to rebuild a transmission in any Toyota. You look at used vehicle prices for Toyota with 300,000 miles on them and they still get huge money for them. A friend bought a 2000 Toyota 4Runner new. It now has 200,000miles on it and nothing has broken on it.

Had transmission fluid replaced at 33,000 miles at dealership ,still having same issues with transmission on GMC SERRIA 6.2L ,slamming on acceleration, shuddering waiting for recall from GMC ,I guess" Good Luck "on that

My transmission guy, who has been in the field several decades, told me that you should never get a transmission flush, rather just get a transmission service where they just change out the fluid, not force flush it.
Hope this helps

I have a 2019 Silverado 8 speed also, I installed a chip to eliminate engine flex it is now a v8 full time. And at same time eliminated the transmission slipping or what seemed like miss shifting

I have the misfortune of owning a 2019 Silverado LT 4wd with the infamous GM Hydra-Matic 8L90 8-speed transmission. I bought it "used" with only 82 miles on the odometer. The original owner returned it after 3 days because, according to the salesman, it was too much truck for him.
I had occasional rough shifts at first but learned how to drive so they didn't happen as often. I took it in and complained and was told "that's normal" and "that's a characteristic of those transmissions". It smoothed out some eventually and I lived with it.
I took the truck in for the recommended transmission service at 52K miles. I would have done it at 45K but I had a family emergency that required me to drive to Houston from Seattle and back. When I took it in, it was fine. I wasn't experiencing any problems with the transmission. When I picked it up afterwards, the service advisor told me it would probably shift rough for 500 miles or so until the computer relearned my driving style.
Things were bad right from the start. It shifted rough and short shifted between some gears. It would downshift and accelerate unexpectedly. It did this on wet pavement and caused it to fishtail. I almost lost control and nearly had a head-on collision. Later, as I was pulling away from a stop, the engine revved to 5,000 rpm but I wasn't speeding up. I thought the tires were spinning but it was the transmission slipping. It finally caught and it felt almost like I got hit from behind. Then the check engine light came on. The truck was dangerous to drive. I took it home and the next morning I took it to the dealership. They took it into the shop to check it out and later called me and told me it needs a new transmission.
I was charged $458 for the transmission service which destroyed my transmission. They charged me $495 for diagnostics fee to determine the transmission was junk. Then the biggie. They said it would be $12,000+ for a new transmission.
I questioned, rather loudly, how it could have failed when it was fine when I brought it in. The service advisor told me it was my own fault for going 7K miles over the recommended service interval. He then told me that the reason it failed was because the dirty fluid was holding everything together. But when they put in clean fluid everything fell apart. He actually said these things to me. Eventually, he said he would speak with the manager and see what they could do to help me out. When he called me back he said they had spoken to GM and GM had agreed to pay half of the cost of replacement. My half would be $6,291.39. That's on top of the $953 they charged me to destroy my transmission. I thought I had the warranty when I bought the truck because we had work done previously "under warranty". That magically disappeared when the trans failed.
Had I done my usual research that I normally would have before making a major purchase, I would not have bought this truck. However, I was offered such a good deal on this one that I knew it would be gone if I didn't buy it right away. Later, after reading about the trans issues, I figured I'd be replacing it at some point during my ownership. I can live with that. I still come out ahead. But I'll be getting rid of this truck asap and I'll never own another new GM product. I'll be buying my vehicles from a different source as well. They're called stealerships for good reason.

To all board members of Chevrolet, judging from my own horrible experience and all these comments, you guys are doing a hell of a job! I wouldn't change a thing. After you go bankrupt from screwing all you customers the government will bail you out. You should be very proud of yourselves! SMH

Working at a used car dealership I'm seeing this often. The truck has a shifting problem, GM says to flush the transmission to try it as a fix. This rarely works. It's been the torque converter having problems. If the torque converter gets to bad the metal bits from the torque converter go through the whole transmission causing major shifting problems. There is a class action lawsuit against General Motors about transmission problems right now.

I don't know what is going on with new improved models, but my 2007.has never had the fluid changed and still runs great. Good mileage ,too.

It's not the flush that's bad, if you'll notice each owner had a concern and thought the flush would fix. Problem was already there. 8 speeds have all kinds of updates and replacement upgrades. Also cooler needs to be replaced after transmission failure.