2019 T1 8 speed Shifting

bearded_warrior · March 26, 2019

Hello,

Has anyone else experienced any shifting issues on their 2019's? The big one I seem to get a hard shift point around 2-4k RPM coming off a stop under light gradual acceleration shifting from 1st to 2nd gear. It's fairly random but seems to be more common after the transmission heats up 150-160 degrees or more, though it'll happen cooler too. The other is when feathering the throttle in traffic the downshifting seems a little harder than it should be, not as hard as the upshift and it doesn't clunk like my old 16' but it's a feeling like driving over a small bump occasionally but it's happened enough while watching the RPM needle shift to think it's not just the coincidence of running over a little bump. Typically during low traffic speeds < 30mph.

All in all, the transmission is a vast improvement and is way smother compared to my clunky 2016 5.3L 6 speed Z71 which I traded in with 35k miles after valve sticking issues and a transmission rebuild replaced a fair bit of the transmission (torque converter, valve body, transmission pump).

I cant tell if i'm just sensitive to the transmission or if I have something worth pursuing, service department says to give it 1500/2000 miles while the truck is "learning" as mentioned in other threads, I currently have just shy of 1100. After that I dread the "normal behavior" discussion.

Overall it's a great truck, really smooth overall and a beast on the open road, in fact it's so smooth most of the time I think it might make the slow speed hiccups seem worse than they are. It's just a concern knowing that if it starts shifting issues at 500 miles, what's it gonna be doing at 20k miles etc..

Thanks everyone for reading! What's your experience?

2019 Silverado 5.3 V8, 4x4, Z71, RST

Limelight · March 26, 2019

Mine is getting better the more I drive it, but it's still confused at times. Yesterday while coming to a stop it lurched and made a small bang- enough that my wife gave me the raised eyebrow look, lol.

Like I said though- it seems to be learning my driving style and improving every day for the most part.

econometrics · March 27, 2019

I just got the same truck you have, OP... Z71 RST 4x4 with the 5.3L / 8 speed / 3.23 rear.

I'm coming from a 2007 LT 5.3L with the 5-speed transmission, so this 8-speed is entirely new to me. But on the way to work this AM, I did seem to feel some similar things from my RST when accelerating gently from stop lights.

Then again, I think I'm just feathering this thing too much since it still has less than 250 miles on it.

bearded_warrior · March 27, 2019

20 hours ago, Limelight said:

Mine is getting better the more I drive it, but it's still confused at times. Yesterday while coming to a stop it lurched and made a small bang- enough that my wife gave me the raised eyebrow look, lol.

Like I said though- it seems to be learning my driving style and improving every day for the most part.

Thanks Limelight, glad to hear it's improving. I sometimes forget, it's not just having to learn my driving style, but everyone else i'm stuck in traffic with too. :-) Fingers_Crossed.

24 minutes ago, econometrics said:

I just got the same truck you have, OP... Z71 RST 4x4 with the 5.3L / 8 speed / 3.23 rear.

I'm coming from a 2007 LT 5.3L with the 5-speed transmission, so this 8-speed is entirely new to me. But on the way to work this AM, I did seem to feel some similar things from my RST when accelerating gently from stop lights.

Then again, I think I'm just feathering this thing too much since it still has less than 250 miles on it.

I'm wondering about the feathering too, I read some things in other threads about it, I tried spending some time either being in or out or consistent with the throttle in traffic this morning and it seemed a little happier. The truck really doesn't seem to like when you give it variable adjustment of the throttle and seems to be happiest giving it a steady throttle position or all the way out. Hopefully it learns.

Sierra Dan · March 27, 2019

21 hours ago, Limelight said:

Mine is getting better the more I drive it, but it's still confused at times. Yesterday while coming to a stop it lurched and made a small bang- enough that my wife gave me the raised eyebrow look, lol.

Like I said though- it seems to be learning my driving style and improving every day for the most part.

Sounds much like the 8 speed woes over on the K2 forum.

Life is like a box of GM Transmissions..... You never know what you're gonna get!

Limelight · March 27, 2019

I tell you what I noticed today too...

I was driving some hilly country roads so I put the shifter in 7L and wow, what a difference. It pretty much stayed a true v8 most of the time (much easier for me to tell now that I have the Magnaflow muffler). When it did deactivate some cylinders it seemed to be at the "right" times, not every single chance it gets an opportunity. The shifts were much better too- it didn't lurch as much when trying to downshift and the shifts seemed smoother. That leads me to believe the fuel management has to make it's changes before the tranny can do what it needs to. Pure speculation there.

Thing is, I was thinking to myself- Man, this tranny is really getting much better... and then I realized it was in 7L still.

It may be a pure coincidence, but the Autostop was on the entire time yet it did not activate once. Every time I stopped the truck kept idling. Maybe this was all a dream...lol.

Need more first hand experience from others to see!

JR09country · March 27, 2019

Mine has smoothed out a lot, I was getting some hesitation from 1-2 shift and then some shutter from a 2-1 down shift, but recently it's been very smooth. The shifts on moderate acceleration if fantastic and seems to keep the truck exactly where it needs to be.

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ShamrockShooter · March 31, 2019

Mine has smoothed out a lot, I was getting some hesitation from 1-2 shift and then some shutter from a 2-1 down shift, but recently it's been very smooth. The shifts on moderate acceleration if fantastic and seems to keep the truck exactly where it needs to be.

Sent from my ONEPLUS A6013 using Tapatalk

I sure hope so. I have only had mine for 2 days and notice a lot of 1-2 and 2-1 clunks/very hard shifts under light accelleration or coasting to a stop. The other trucks I test drove did not do this, including the one I did an overnight test drive with.

So I too have fingers crossed this will go away.

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SierraAT4 · March 31, 2019

I doubt this is helpful, but I thought I would mention that the in the 1500 miles I have on my AT4 (6.2), the 10 speed has never once been confused...no high revving, no searching for a gear, no clunks...it just always seems to know what gear to be in.

I've never noticed a transmission so little in a vehicle before. They keep this shit up and they can just go ahead and remove the tach from the dashboard.

bearded_warrior · April 19, 2019

Quick update: the 1st-2nd clunking is still very prevalent at 1700 miles. I've also found the theory of being steady with the throttle helps a little bit for driving in traffic. In/Out/Steady vs feathering the throttle. It's reduced some of the jumping feeling between predictive shifts.

econometrics · April 19, 2019

Thanks for the update!

I just crossed 1000 with mine. Not noticing the 1-2 shifts as much, but I do still feel them from time to time.

I’ve also noticed that random times I put the truck in D and have to give it more gas than usual to get it to move forward. Not a lot, but more than just putting it into D, letting off the brake and naturally moving forward.

Limelight · April 20, 2019

8 hours ago, econometrics said:

Thanks for the update!

I just crossed 1000 with mine. Not noticing the 1-2 shifts as much, but I do still feel them from time to time.

I’ve also noticed that random times I put the truck in D and have to give it more gas than usual to get it to move forward. Not a lot, but more than just putting it into D, letting off the brake and naturally moving forward.

That's usually because the parking brake is set, it'll release in D when you give it some gas. Sometimes the PB sets itself automatically. Couple of threads on that already.

econometrics · April 20, 2019

17 minutes ago, Limelight said:

That's usually because the parking brake is set, it'll release in D when you give it some gas. Sometimes the PB sets itself automatically. Couple of threads on that already.

Without an indication in the dash? I set mine every night at home (driveway is inclined). But last night I was totally level when parked. No light on the dash. Had to apply some gas to get it going.

Limelight · April 20, 2019

1 minute ago, econometrics said:

Without an indication in the dash? I set mine every night at home (driveway is inclined). But last night I was totally level when parked. No light on the dash. Had to apply some gas to get it going.

I'm pretty sure the light is on- maybe you just didn't notice. Happened to me- I mean you really wouldn't look if you knew you didn't set it before, right? Once I read that thread I figured out what was happening.

Bikeman · April 21, 2019

I have 1500 on mine and the only time I notice the 1-2 clunk is when the trans isnt warmed up. I'm thinking hard shifts are a characteristic of the 8 speeds. I traded in a 16 with the 8 spd and the 19 is noticeably smoother and the weird whistling sound the 16 had is not present in the 19? Idk