I've had the second transmission flush, and it does not shudder as bad. However, I've driven it over 200 miles & don't think the problem is entirely fixed. My dealership has been helpful and understanding and reassures me I have warranty coverage. I am 77 years old and will be driving from MI to FL next month (with a lot to get done before I leave) and am trying to decide if it will be beneficial to take the truck back to the dealership and add shuffling cars to my to-do list, or if I will be comfortable driving it that distance and away from my local dealership. Any thoughts?

Didn't know what the problem was at first. It felt like the transmission was having trouble shifting under normal conditions. I took the truck in for an oil change and complained about it. The service department clerk did not say anything about a problem with the Colorado in reference to the transmission and they quietly flushed the transmission and gave the vehicle back.

Later on I spoke with a friend who is a Corvette fan and a Silverado owner and he told me it was a bad torque converter. He said it was prevalent in the Colorados and Canyons. Well, the flush seemed to have worked, but a few months later the problem started again. I took the vehicle back and complained and the mechanic drove my vehicle and said there was no problem. I drove home and noticed a difference, the shifting had improved. I believe they made some adjustment and did not note it on my paperwork.

Now a few weeks later the problem is starting again, with an addition. When I pull into a parking space and shift to park, the transmission shifts up and the vehicle lurches forward. Thankfully the brakes hold. I am so disappointed in Chevy/GM. I bought this truck as my retirement present. I am a Chevy person and also own a 2011 Camaro, which I love. I am glad I kept the Camaro as I believe I will need dependable transportation in the near future. I purchased an extended warranty when when I bought my Z71 but I bought it for my piece of mind and not to protect me from shoddy workmanship. GM has been aware of this problem since 2015 - COME ON, 5 YEARS!

I bought my ZR2 in December of 2018. Never have I bought a new vehicle of my own, always used. This truck is my baby! The truck was bought with a starting mileage of 225mi due to dealership transfer. About 3 days after buying it I noticed the lurch or jerk during stop and go actions. Immediately I expressed my concerns about a potential transmission issue to my father and we both decided it was potentially just due to it being a brand new vehicle. Occasionally once in a blue moon in the next year, I would feel the shudder or rumble strip feeling and chalked it up to potentially rough roads or tires losing grip.

Now here we are. Within the start of this year, the shudder has gotten worse and more consistent. It will happen during any acceleration periods or in 5sec or more intervals at speeds between 25-80mph. I took the truck to firestone for a potential balancing issue which turned into them telling me it is something with the transmission or torque converter. During my drive today it has gotten even worse with a jerking feeling while on cruise control to maintain speed as if it is having a hard time getting into gear and staying there.The dealership service department opens up on Monday so I will keep everyone up to date on this process. I am less than 20,000 miles away from the end of my powertrain warranty.

For all knowledge, I did my research and have all my ducks in a row which I would like to share. The 2015-2017 models were equipped with the transmission model number 6L50. There is an ongoing lawsuit in California on this defective transmission, all reporting the same issues that I have read on this forum. With some easy digging Colorado 2018-2020 are as well equipped with these transmissions.

Due to how late I am coming into this issue realization I don't believe a simple transmission fluid replacement will be a fix.

I bought this 2018 Chevrolet Colorado Z71 4x4 crew cab long bed 3.6L V6 with 6,500 miles on the odometer in February of 2019 and began to experience the transmission shudder/vibration a few months later in the summer time. This issues slowly gets worse the more miles you put on. This was covered under warranty by the dealership by flushing the transmission fluid and replacing the transmission filter. After the repair, the issue was resolved the truck is approaching 25,000 miles with no transmission complaints.

I experienced a shutter in the Transmission similar to running over a rumble strip as some others have described in other complaints. I brought the Truck into the Dealer who told me they have a fix.

The Dealer changed the fluid in the transmission and sure enough, it did fix the Transmission rumble effect I had experienced. It even shifted better than it had before. I drove it about 1000 miles or so and guess what? It did it again... but not so often. Most at higher speeds around 50-60 MPH. I don't know whether to take it back to the dealer and ask them to.... what?! Change the fluid again? Same results? What do you do at this point?

So far it is still driving and shifting and only does the rumble thing every now and then. I am concerned that after the warranty runs out, it is on me for repair. It is more of a nuisance than anything else at the moment. Come on GM help us out.

Bought this truck in July 2018, started feeling shudder at about 7500 miles, Dealer said just needed to flush and replace with new fluid, that took a week. On the way home started doing it again, waited a few weeks they tried again, this time 2 weeks in shop, few weeks later, same thing, this time they tell me they will replace torque converter, two more weeks in shop. Meanwhile the general manager tells me they really don't have a fix yet. Well needless to say, about 7500 miles after the new converter, it's doing it again, but worse. I am at the point of hiring a lawyer. GM knows they have a serious problem, they just haven't figured out how to fix it. And they don't want to do a recall.

Transmission shudder started around 7300 miles at around 45mph. Problem steadily got worse, called dealer had to wait for 3 weeks for an appointment. Took vehicle in on Nov. 4th, took 2.5 hrs for them to flush the trans and replace the fluid with Mobile 1 fluid. So far it seems to have corrected the problem, been just over 150 miles.

Will see how things go.

Update from Nov 17, 2019: Took vehicle to dealer 2 weeks ago. They flushed the trans. And put in the new Mobile 1

Trans. Fluid... so far it’s good added about 200 miles and no more transmission shudder.

I have a 2018 Chevy Colorado that I bought new from dealer 8 months ago. The dealer had used it as a service loaner and it had 3,000 miles on it. I now have 15,000 miles on it. It has begun to shudder constantly when accelerating or decelerating. I contacted service dept at dealer and they said they know what it is but could not give me an appt. for 2 weeks. I am afraid if I drive it. It will cause further damage but they don't seem to care!"

I am trying to be included in current class action suits already filed for this. If not, I plan to pursue starting one

Update from Sep 3, 2019: I took my truck in instead of waiting for appointment. The service department was much more responsive than the person I talked to on the phone who said she could give me an earlier appoitnment and she could not guarantee when it could be fixed if I brought it in when I requested an earlier appointment. The service manager was very responsive when I just brought it in. They did a transmission flush which so far has worked so I am satisfied at this time

Well this is disappointing, I have noticed a shudder on my 2018 Colorado for a few months now. It started when I was driving on a slight hill at 75 mph on the interstate. Over the last few months it has gotten worse and I can feel it now driving from 45 mph and up. It seems worse in the overdrive gear. I finally had someone look at it, and they immediately said that it was the torque converter. I plan on calling my local dealer and scheduling an appointment but it sounds like this will only be a temporary fix. Fingers crossed this will be covered on the powertrain warranty. I wish I had done more research before buying this truck, I bought it used at 25k.

Same as others on here with the vibration or "driving on rumble strips" problem.

I notice a vibration or rumble from what feels to be the rear end of my truck (2018 Chevy Colorado WT, Crew Cab, 3.6L V6 - tow package, automatic transmission) in the 1500-2000 rpm range at constant speed/accelerator pressure. When I let off the gas or accelerate it stops and doesn’t resume unless the tach drops back down to 1500. No lift, or level, or new wheels or tires; truck is stock. I notice this at worst times around the 35-45 mph range but notice it at higher speeds as well, but agoing only under the conditions of constant/steady speed and pressure on the accelerator at the 1500 to 2000 rpm range specifically.

I have dropped the automatic transmission into "manual" mode a few times when this happened to see what gear it is in. It displays 6th gear, but not sure if the problem is isolated to that gear or if it happens at others as well.

I have read the posts on here and in different forums about this and have heard the process of transmission fluid flush, torque converter replacement, transmission replacement. I will contact my dealership tomorrow and will update with what the outcome is.

2018 Colorado WT

Mine developed a bad shudder early on. The fluid flush did not solve the problem. They replaced the torque converter and it was good for a while. This past week (26K) it seemed fine until I stopped at a traffic light. When the light turned green the truck would not go. It would rev up but no go. It gradually started to catch and I crept across the intersection. It continued to pickup speed slowly about a mile away from a dealership. I pulled in, they confirmed it was a transmission problem but they could not get parts. Due to the severe parts back-order situation at GM and the shear amount of transmission problems they have a backlog of work and I have to wait 4 to 6 weeks. They would not give me a loaner so I am having to drive it and hope I make it. If it leaves me on the side of the road I will call GM roadside assistance. I have opened a case with GM and they did nothing but put pressure on the dealership which can’t respond. I would take part in a lawsuit! They need to fix the problem and or pull their reliability commercials off the air.

I can't say more than what was said regrading the transmission problem. I suffer the same problems vibration between 35- 50mph. The truck tries to down shift and then it up shifts when going up steep hills. I am afraid it's going to stall and I will roll backwards out of control. GM please step up and come up with the answer for the safety of the AMERICAN customer. I bought this vehicle to last my lifetime. I am going on 75 can't buy another car as I bought my wife 2018 Equinox which works real well. HELP US!

I took my Chevy Colorado LT into Freedom Chevrolet Dallas, Texas for an oil change and asked them to check for a shudder vibration in the drive train that occurs at 30 MPH up to 70 Mph and is not constant, but will come and go.

The Dealership Service Department found a GM TSB #18-NA-365 that addresses the shudder vibration problem after a #8480818 Diagnostic Test. They replaced the transmission fluid and a part #1941757 (unknown part), road tested my vehicle and it seems that they have fixed my problem.

There was notation on my invoice stating: "Performed transmission fluid change, verified repair, shudder improved, customer will need to drive 200 miles reach operating temperature drive cycle for full effect."

I drove home on the Interstate about 12 miles at an average speed of 70 MPH with an outside temp of 93 degrees and it seems ok now.

Anyone experiencing this problem with their Colorado should take this Service Bulletin info with them for a quick resolution. GM TSB #18-NA-365.

2018 Colorado ZR2 - 8spd Transmission

Transmission shuddering. - Identified variable speed occurrence could happen at 25 or 65. Unrelated to tires/steering or to shock cavitation or rough roads. Happens on smooth or rough roads. Vehicle has not been off-road. Varied inconsistency. More apparent when engine is cold shifting from 1st to 2nd to 3rd then will dissipate. Shifts hard 1st to 2nd and sometimes 3rd when engine is cold. Once warm shifting is smoother but shuddering still occurs. More apparent when engine is warmed at steady RPM/Speed once in 6th - 8th.

Variable speed occurrence - 25 - 65. Began noticing it after about 500 miles. No consistency so was unsure if it was the road I was on or something else. Tires were within spec regarding air pressure/balance. Random issue with no visible consistency other than previously stated. Vehicle has not exceeded 70mph. Vehicle has not towed any significant weight, 5x8 flatbed unladen. Less than 10 miles on surface streets, 1 trip only. Issue occurs both before and after towing. Towing is unrelated as shuddering occurred prior to towing.

Problem I am experiencing is about the same as everybody else. It just started at 1400 miles. Chevrolet seems in capable of fixing the issues. I have started the lemon law process. I have had the oil changed and torque converter changed. Chevrolet is about to put in a new transmission, however I doubt this will fix the problem. It may be a temporary fix but will return shortly. Chevrolet needs to recall these vehicles and install a proper transmission that is reliable. The worst part of the issue is a safety concern when it decides to lunch or walk down shift. It is unsafe to drive and responds in a non-consistent manner, let alone the annoyance of the vibration that feels like you’re driving on the attention strips on the highway.