Hesitation from engine and Hard shift when going forward

[Drew Bellucci]

Anyone else experiencing a hard shift or hesitation of the engine when you first hit the gas. For example, I start the truck, reverse out of the driveway, put the car in drive and when I hit the gas, the truck goes toward and then i feel the truck completely stop for a second (hesitation) and then it continues forward, I only expierence this when I’m going from reverse to forward.  I come to a complete stop and do not shift to drive when moving backwards still. ?

[Jphutch22]

I’ve noticed the same on my AT4

[Chevy sad]

Are you sure it’s not the auto park brake?Mine has similar traits. When backing out of the garage it is always on. Had a few burn out moments until I learned how to release it. It also activates when changing from R to D if I come to a complete stop and let my foot off the brake while on the slope of my driveway. 

The other day I backed out, remembered I needed water and ran and got it. All along the truck was in gear with auto park brake on. 

If you don’t release it before giving it the gas it will lurch. Almost feels like turbo lag. 

[Kingtut38]

I have noticed this on my HC too.

[TBL569]

There is a service bulletin on the 8sp transmissions for your issue.  I had a 17 HC with this and I had it serviced several times for this issue.  It drove me crazy until I finally traded it in.  There is no fix but they may do a relearn on yours like they did on mine.  It helped for a few weeks but returned to the normal harsh shift between 1 and 2 upon the first start up if the day.  Unfortunately they told me that the transmission was "operating as designed".  If you keep your truck look into an aftermarket tuner.

 

[Wiggums]

I am having the exact same thing and I think the transmission is hunting for gears sometimes. A few times, I had it jerk back and forth, especially at very low speeds.

 

I thought it was the auto/stop causing the hesitation so I turned it off along with AC on full blast but it did that still.

 

It also created a safety issue for me because I had just turned on a straight road that was dirty then let off the gas about 20 feet before the dirt patch. The transmission shifted with a loud clunk, causing the rear wheels to shudder on a rough terrain and the back end was about a foot off. I had to suddenly jerk the steering wheel. That being said, I think it was due to the transmission, I was going only 35 mph and had slowed down by removing my foot off the gas before hitting that patch.

 

I mentioned that in another thread and the fanboys were all over me for that one. I'm surprised they're not here attacking you.

[Drew Bellucci]

Seems like others are having the same issue on other forums too. The “fix” is an aftermarket tuner is what I’m being told.  Only happening in the 5.3 8 speed.  This is my 7th Chevy Silverado. It’s a very noticeable lag and jerk when I’m at low speeds. Also told it may be the engine relearning.  I only have 1500 miles on mine so, I guess time will tell. 

[Wiggums]

Others said to get the AFM (Active Fuel Management) disabler but the 2019 models have DFM (Dynamic Fuel Management). I think all RST's have DFM.

Only 360 miles on mine and it's very unsettling. I'm starting to suspect it was responsible for shifting my rear end on a dirty road about a foot off, placing me at a dangerous angle while driving on a straight road, forcing me to suddenly jerk the steering wheel.

 

That could be a liability issue for General Motors. They can easily look at the dirt pattern to see that I wasn't accelerating or braking. One could look at the dirt and see that the rear wheels changed gears suddenly, causing the truck to be off angle-wise. The "black box" in the truck will verify I wasn't speeding.

[ShamrockShooter]

Look up bulletin #16-NA-361 harsh 1-2 shift upon first startup shift under light throttle. GM says it normal on the 8 speed. It has something to do with the initial clutch fill time of the C4 clutch. No fix for it. Gm says it's normal. I have driven more than one 2019 8 speed and they all do it.

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[anthony2558]

Same here. Harsh down shift when slowing down, sloppy trans, I had my foot on the brake, put it in drive and with out taking my foot off the brake the f'ing thing start to slowly pull forward. I pressed down on the brake harder, there was a lot of play in there.  Almost like the brake booster gave out. I don't know whats going on but after 800miles I'm really starting to hate this truck. 

[bearded_warrior]

Just found this but i've been pushing pretty hard on GM to get someone to look at it. Short is no one will touch it unless they can repeat it at the dealership.  I've got a thread going on my experience so far, which is.. disappointing. 

[zzrsouth]

On 3/17/2019 at 6:40 PM, Drew Bellucci said:

Anyone else experiencing a hard shift or hesitation of the engine when you first hit the gas. For example, I start the truck, reverse out of the driveway, put the car in drive and when I hit the gas, the truck goes toward and then i feel the truck completely stop for a second (hesitation) and then it continues forward

Mine does this every morning from a cold start and I pull straight out.  My current mitigation strategy is to touch the gas pedal softly and then coast a bit so the transmission has time to 'get normal'

 

Just a quirk of our machine.  The shudder on deaccel is far more annoying to me.

[UGADawgs]

I have the same cold start 1-2 shift hesitation and lunge. I do the same coast method as zzrsouth. Once in 2nd, can't stop, accelerate and reproduce. It doesn't happen again until the next morning. So it does feel like the clutch fill as shamrockshooter explains.

[rikhek]

My 2019 8 speed AT4 experiences the hard shift as described in post #1.  It does it hard enough that it scares me.  It only happens occasionally and on a random basis.  It seems to only occur after the first start of the day.  I'll reverse out of my driveway, put it in drive and go 20' or so, it will hesitate and then HARD SHIFT/SLAM into gear.  What's interesting is it only does it occasionally and it's unpredictable.  As such, when it does it it scares the hell out of me.

Edited July 9, 2019 by rikhek

[Walter Gill]

I am having the same issue. 

The dealer keeps telling me it is operating as designed 

it clearly isn’t. Hesitation, hard shift, surge forward, sometimes almost dies at idle and sounds like it misses in the exhaust on occasional start up.