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2019 Silverado LD 6 Speed harsh first shift 2-3 after cold start

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Hello, as per the title my 2019 Silverado Z71 LD (classic style) LT truck with a 6 speed transmission shifts harsh from 2-3 after a cold start. It only shifts harsh upon the first shift after a cold start but is fine after that.

I only have 10,000 kms on this truck. This happens with a normal light throttle, I have tried with more throttle but the shift is still somewhat harsh. I brought it in but they couldn’t reproduce the harsh shift, as per dealer there are no TSB’s for my trucks transmission.

I have yet to drop the truck off overnight at the dealer to see if they can reproduce the issue.

Does anyone out there know the actual cause of this? Or does anyone know of a fix for this?

Please help, thanks, Dwayne

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Sorry long post


Have had this problem with my 2017 LT 2wd, 1500, crew cab, short bed, has 25000 miles, 10,000 towing rear end ratio.


Have had it at the dealer, at least 5 times, no fix, no TSB's, no oil change (same problem with 2500 trucks, fix was to replace the trans fluid because the one they put in was not the correct one. they had a recall) 


They wouldn't do anything, I wanted to do a Lemon Law complaint, in CA you can do it. some people think that this is only valid while the 36,000 miles or 3 year bumper to bumper. But the running gear is guaranteed to the 50,000 or 5 yr.


So the problem I have is that the 3:42 rear end ratio. And I can't find that normally on a 1500 in 



When I bought mine it was one of three 2017's they had. So it was pretty happy with it..


I have also upgraded it myself to what an LTZ would have, signal mirrors,  auto-dimming rear view mirror with auto-dimming left side mirror, programmable garage door opener, etc. Also shaved off all emblems, GM bed lighting, K&N filter, Nissan Titan XD diesel Tires and Wheels (5 of them). a second set of matching horns. big trailer connector extension to give me a 4 or 5 prong trailer connector to connect a below tailgate LED lights. Grillcraft mesh grille insert. GM running boards flat ones, chrome and powder coated semi-gloss black.


So If I change the truck I would have to remove all this stuff, because I would not want to give GM the stuff that I installed....


At least I have a 6 year, 100,000 mile $100 deductible insurance. which would cover the tranny if it goes to hell.


Good thing is that there are lots of Silverados with lots of miles with them with the exact driver train.


And my truck will burn rubber off the line and surprises tons of other Silverado owners from Stop lights to Stop signs....

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God I wish some dealers would search harder.  Normal condition, they all do it.  Both of my 6L80s do/did it (2019 LD 1/2 ton and 2012), my 6L90 (2015 HD) did it as did my 6L50 in my Colorado.   




#PIP5429A: 2-3 Upshift Slip or Flare - (May 8, 2020)

Subject: 2-3 Upshift Slip or Flare

Involved Region or Country



Some customers may comment on a 2-3 upshift slip or flare.


This condition is a NORMAL characteristic of the transmission, it will not cause durability concerns and no repair attempts should be made.

Service Procedure

At this time this flare condition has been recognized in two different driving conditions:

  1. During the first 2-3 upshift after the vehicle has been sitting, engine off for several hours..

    This condition may be caused by air that is trapped in the 3-5-R clutch assembly.

    When the first 2-3 upshift is made this trapped air is purged and the following 2-3 shifts will be normal with no flare.

    When diagnosing this condition a garage shift into reverse before drive will purge this air and prevent the 2-3 flare from occurring

    This condition is a NORMAL characteristic of the transmission, it will not cause durability concerns and no repair attempts should be made.

    Please communicate to the customer this will not impact the designed performance or reliability of the vehicle.

    Please share this information with the customer, including a copy of this message.

  2. When transmission ATF temperature is at or below 85 degrees F (30 degrees C)..

    This 2-3 upshift flare can occur until the ATF temperature warms.

    If the 2-3 flare is determined to be ATF temperature sensitive use a Tech 2 or GDS2 to make note of the throttle position when the flare occurs

    Drive the vehicle to get ATF temperature to at least 104 degrees F (40 degrees C) and then make several 2-3 shifts at the throttle position determined to be the most sensitive to the 2-3 flare.

    This will allow the transmission adapts to tailor the shifts and may help to eliminate the cold 2-3 flare.

    This condition is a NORMAL characteristic of the transmission, it will not cause durability concerns and no repair attempts should be made.

    This condition is a NORMAL characteristic of the transmission, it will not cause durability concerns and no repair attempts should be made.

    Please share this information with the customer, including a copy of this message.

Notice: A revised TCM calibration has been released and is available on TIS2WEB to improve this concern in 2007 vehicles equipped with the 6L90 RPO MYD automatic transmission.   



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I have this as well in my 2018 Sierra 1500 with the 6L80E trans.....usually only when it sits outside in freezing temperatures. From 2nd to 3rd gear, feeling of a big "clunk" in the driveshaft...then completely normal from there on.  I seriously thought my transmission had exploded the first time I experienced it. 


I installed a 100W transmission pan heater pad and plug it in for a few hours in the morning when it's freezing out, it usually raises the temp of the trans fluid between 10 - 15 degrees celsius, and combined with remote start 5-10 mins prior to driving, sometimes this has helped reduce the clunk.


As the memo above indicates, I never have this issue when the trans fluid is above 30c.


A friend who's been a GM tech for 25+ years confirmed it's normal, and nothing to worry about. 


Edited by YYC-SIERRA
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Thanks to all you guys that replied to my post.

Special thanks for the bulletin on this issue.

This harsh shift is less noticeable now that the temps in my area are getting above freezing, finally.

It is still harsh even when going in reverse first before forward.

AT ANY RATE: This is bullcrap that GM couldn’t even be bothered to fix this issue, they can call it normal all they want but its a flippin’ defect for sure. Any idiot knows that repeated harsh shifts will eventually wear/ break apart clutches, not to mention metal fatigue over time!


Thanks to all, Dwayne

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  • 3 weeks later...

Ps..from what I read an upshift slip or flare is actually when the engine will rev higher (slip) just before the completion of the shift.

My issue is a harsh thump only without a smooth shift, re..without the slipping or engine revving higher.

So that bulletin may not be my issue.

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