2019 Tranny slippage or shuddering issue

[MiCar Info]

I've read a lot of post about the converter being the culprit causing the shuddering problem. Many of you have described the problem as "shuddering" caused by the converter. It sure seem like tranny slippage to me. I purchased a new Colorado Jan 1st, 2019 i began having this shuddering/slippage problem at 2131 mile. I thought maybe it will pass, could be a break-in issue. Everyday i pull out of my driveway reach the street and begin to accelerate to about 25 mph. Feels like tranny slips out of gear for a few seconds and then runs fine. At 4145 mile I take it to the dealer explain the issue they claim they can't duplicate the problem. The problem persist everyday like clockwork but then it start happening on the road slipping in and out of gear for a second. I take it in at 9059 miles I said don't give it back until its fixed they keep it 3 days, i pick up my truck ask were you able to duplicate the issue? Yes, the service mgr says and we fixed the problem. I asked what the issue was he could not elaborate, the next morning same thing. At this point I decide to begin documenting every occurrence & repair attempt. I'm over 15,000 miles and now 5 additional failed repair trips to the dealer.  There's no recall yet and i am convinced GM knew about this problem for some time. I'll fight this thing to an arbitration remedy since I don't see an alternative solution. It's just unfortunate you pay good $$ for a new vehicle only to have mechanical problems from the beginning and the dealer pretends the problem doesn't exist. I've bought 4 new american cars/trucks the last 15 years each has made me wish I had purchased toyota.

[carloliveira]

Sounds like the tranny shudder, did your repair invoices say they did a flush and fill or replace the torque converter at any time? After 3 repair attempts you may qualify for lemon law. Or try a different service department, not all are created equal.

[flyingfool]

what trim options is your colorado,  did you get the 6 speed or 8-10 speed trans?

 

[Boatangler]

Interesting,  my 2018 also has a vibration/shudder,  actually more like a vibration when I have to give it a little gas to maintain speed but not enough for a downshift. I read elsewhere another owner was told it was a design flaw but there's no recall for it, multiple responses also mentioned having the transmission flushed and refilled using a synthetic fluid like Mobile One usually fixed the problem 

[milkmaster]

My 2021 does the same type of problem.  It does it especially when it is very cold outside.  The truck starts off in first gear and then nose dives for a split second when it tries to shift into 2nd gear.  It only does it the first shift of the morning and then it is fine.  Warmer temperatures outside eliminate the problem.  Mine is a 5.3 w/8 speed transmission.  Right now it has 7500 miles.  Did this all winter when the mornings were very cold.  I met another fellow who has the exact same truck as me, and he described the same situation.  Otherwise the truck has been flawless.

[madcratebuilder]

Sounds like solenoid timing to me.  The "shudder" feels like driving over rubble strips on the hiway.

Google "8L45-8L90_ATRA.pdf"  Down load and read the document.  It walks you thru the driving mods to rest the solenoids.