2019 5.3l 8 speed jolt when accelerating

zzrsouth · May 1, 2019

I know exactly what OP is talking about but my trucks behavior does seem to be improving with miles (or Im getting used to it). Occasionanly I get it when deaccelerating also and always find the 'jolt' more alarming when it happens then. I've gotten so I use a bit firmer brake pressure to prevent unintended movement instead of just rolling up to lights.

Bmwtech113 · May 2, 2019

I contacted GM and they have already reached out to my dealer. They want me to bring it back in to “get more information” from my truck.

UGADawgs · May 3, 2019

Yesterday I was making a quick turnaround by pulling into a driveway, tossing it in reverse, and then right into drive. Maybe I shifted too quick without being at a complete stop, but the truck started moving forward maybe a couple feet and then blam, heard a sound from the rear end and the truck lurched forward like we were rear ended. It was a bit violent. Engine was warm as it was after a solid hour drive. The girls in the truck both said "what was that?!?!"

econometrics · May 3, 2019

On 4/30/2019 at 9:39 AM, UGADawgs said:

I have the same lunge from 1-2nd if it's cold and I lightly accelerate. If I give it half throttle when cold, no issue. Also, no 1-2nd shift issues when warmed up.

8 hours ago, UGADawgs said:

Yesterday I was making a quick turnaround by pulling into a driveway, tossing it in reverse, and then right into drive. Maybe I shifted too quick without being at a complete stop, but the truck started moving forward maybe a couple feet and then blam, heard a sound from the rear end and the truck lurched forward like we were rear ended. It was a bit violent. Engine was warm as it was after a solid hour drive. The girls in the truck both said "what was that?!?!"

Yeah, get in line, OP. We're all having these issues with our 8 speeds. Lol!

My issues have been like UGADawgs'... whenever I baby the throttle, I notice the harsh shifting more than when I just drive the truck with a little assertiveness.

Had the SAME thing happen last weekend when putting the truck in R, then right into D... harsh thump in the rear right after I started moving forward in D.

Bmwtech113 · May 4, 2019

To clarify, I do notice harsh shifts as well, but my main issue is more of a shudder or a misfire type feeling not during shift points.

Dealer called me twice today. First time was the technician asking some questions and said he could try the new fluid but wasn’t sure it would fix the issue. 2nd phone call was the service advisor saying that my truck drives like all other 2019 trucks and there was nothing they could do and that maybe there will be a software fix or something in the future. The service advisor also said that my truck already has the new fluid.

bearded_warrior · May 4, 2019

Mine goes in next week for the same issues, hopefully I hear something different. They also quoted the TSB that describes the 1-2 shift as normal after a cold start. Since mine is happening more than just cold starts and in other gears than just 1-2 they're taking a look at it.

For what it's worth, the 8 speed is still way smoother than my 16's 6 speed which had parts of the torque converter sheer off and cause other issues at less than 35k.

econometrics · May 4, 2019

My 8 speed sounds like it’s doing much of the same things being reported here. It’s not really all that concerning to me, and usually not too harsh either. But I think I judge the transmission with more scrutiny because it’s brand new and a brand new trans itself.

Coming from a 4 speed with OD in my 2007, it’s also VERY different feeling to drive up to 60mph.

Therefore, based on what I am reading here, I’m not going to take it to the dealer until there’s a real fix from GM with reported success by many owners. Until then, it’s under a 3 year / 36K warranty so I’ll keep enjoying it!

Eljeffe316 · May 4, 2019

My 2019 AT4 did this for the first time today at 3k miles... actually thought I was rear ended it jolted so hard. Did feel like the trans slipped in some way. Just backed out of the drive and switched from R to D - also was on a cold start.

Bmwtech113 · May 10, 2019

Just picked my truck up from the dealer again. They replaced the transmission fluid with the new fluid. Turned left out of the parking lot and accelerated up to 40.....still doing the same exact thing.

**Edit**

its actually worse now. I just finished a 30 mile interstate drive and I can definitely feel a shudder with light throttle on an incline.

Edited May 11, 2019 by Bmwtech113

bearded_warrior · May 10, 2019

see this thread if you haven't -

What I Posted yesterday:

Quote

TLDR; "NORMAL"

They Referenced: SI Doc 4605342 - 1-2 shift on cold trans considered normal.

Even though mine shifts hard when warm and more gears than just 1-2. Test drive and TAC Case was deemed normal.

Regarding the transmission, there were no attempted "fixes" "flushes" or anything. They also mentioned that the software is "restricted" to their techs so not even they can look to see if it's the latest version.

This is like Deja Vu with my 16' which had a transmission rebuild at 3 years 35k miles. Though I will say, compared to the 19' 6 speed 1500 Custom I had as a loaner, my19's 8 speed feels majorly smoother.

At least they "tried" something. I think it's just too early to tell. New platform, no "fixes" but at least we're bringing it to their attention.

Also, Mine makes noise when pulling away in the morning, humming noise under the vehicle during light acceleration first pull away, "That's the Transmission building up pressure." - Normal.

MOHouston · May 11, 2019

I’ve also noticed this. Monday will be 3 weeks since buying brand new Trail Boss LT. My friend has a 2016 or 2017 (I’ll have to check to be sure) and he said that’s completely normal for his as well.

But today the girlfriend even noticed it, now it’s bothering knowing it’s there....

HondaHawkGT · May 11, 2019

19 hours ago, Bmwtech113 said:

Just picked my truck up from the dealer again. They replaced the transmission fluid with the new fluid. Turned left out of the parking lot and accelerated up to 40.....still doing the same exact thing.

**Edit**

its actually worse now. I just finished a 30 mile interstate drive and I can definitely feel a shudder with light throttle on an incline.

The light throttle shutter at highway speeds could be caused by DFM as it switches between firing patterns. It's hard to tell since we are only going off of written descriptions of what you're experiencing. Has somebody from the service center ridden along to see what you're experiencing, or perhaps allowed you to drive a new truck to see if other trucks do the same thing?

Edited May 11, 2019 by HondaHawkGT

Bmwtech113 · May 11, 2019

58 minutes ago, HondaHawkGT said:

The light throttle shutter at highway speeds could be caused by DFM as it switches between firing patterns. It's hard to tell since we are only going off of written descriptions of what you're experiencing. Has somebody from the service center ridden along to see what you're experiencing, or perhaps allowed you to drive a new truck to see if other trucks do the same thing?

A technician did ride with me for my initial complaint and felt it once. Of course it happens more often. I just noticed the highway light throttle shudder after I picked it up last night after the trans fluid flush. I could just be more alert because I’m looking for the other issue.

coyt80 · May 12, 2019

YES That is so annoying. I get it in both directions but harder when downshifting from 2-1.

ILSilverado · May 13, 2019

On 4/29/2019 at 8:39 PM, Bmwtech113 said:

I have a 2019 AT4 with the 5.3l engine. I’ve had it for about a month now and I have noticed especially when I first take off after the truck has been sitting for a few hours that there is a jolt that will happen multiple times while accelerating up to speed. I’m not flooring it, just accelerating normally. It occurs between 10 and 50 mph and once it warms up then I never notice it again. Happens in D and also if it put it in L7 or L8. It feels like either a misfire or the transmission slipping. I just picked it up from my dealer tonight after they said “we’ve had other complaints but that’s just how it is.”

Has anyone else experienced this?

Yea the A8 is the worst shifting transmission I have ever owned. I have it in the 1500 and two Corvettes. It behaves the same way in the Corvettes as it does in the 1500. This class action is a long time coming. On my 2015 Corvette it used to just slip out of gear rev then slam back in with a horrible jolt and GM refused to replace the transmission. Seems like GM is just making high priced junk these days.

Edited May 13, 2019 by ILSilverado