23 GMC Sierra 10 speed trans

Sean Rankin · January 25

Transmission Observation:

I just traded in my 2017 GMC Sierra 6.2 with 8sp trans for a new 23 GMC Sierra 6.2 with 10sp trans. I loved my old truck. It had 90k miles, ran great and never gave me any issues. One of the things I liked most about it was the motor and performance. It sounded great (muffler delete), and felt quick for a truck. The transmission always shifted very solid and always surprised me how crisp the shifts were.

My new truck, a 2023 Sierra AT4 6.2 with 10sp has a 6in lift and 35 in tires. I love the way it runs and looks. I don't like the transmission. It seems sloppy. You can barely feel the shifts, there is no predictability, and it almost feels like the torque converter is constantly locking and unlocking. I'm not sure if it has anything to do with the lift and tires, but it's a bummer. I even tried putting it in sport. The 2017 transmission almost felt like a sports car....the trans on my new truck feels lost and slushy. Anyone else experience this?

Edited January 25 by Sean Rankin

gemarsh · January 25

How did the tranny feel before adding the 35's?

I would have a hard time believing a lift would have anything to do with the sloopynees you feel.

Bikerjon · January 26

On 1/24/2024 at 6:14 PM, Sean Rankin said:

Transmission Observation:

I just traded in my 2017 GMC Sierra 6.2 with 8sp trans for a new 23 GMC Sierra 6.2 with 10sp trans. I loved my old truck. It had 90k miles, ran great and never gave me any issues. One of the things I liked most about it was the motor and performance. It sounded great (muffler delete), and felt quick for a truck. The transmission always shifted very solid and always surprised me how crisp the shifts were.

My new truck, a 2023 Sierra AT4 6.2 with 10sp has a 6in lift and 35 in tires. I love the way it runs and looks. I don't like the transmission. It seems sloppy. You can barely feel the shifts, there is no predictability, and it almost feels like the torque converter is constantly locking and unlocking. I'm not sure if it has anything to do with the lift and tires, but it's a bummer. I even tried putting it in sport. The 2017 transmission almost felt like a sports car....the trans on my new truck feels lost and slushy. Anyone else experience this?

The transmission in my Trail Boss operates very smoothly. I can barely detect the gear changes. I sort of agree with you. I would prefer a more solid gear change. You used the word crisp and I definitely would not describe the shifts as crisp in my 23 w/ 10 speed. I only have 2800 miles on mine so far. Not to scare you but you should search the 2019-2023 Silverado & Sierra Troubleshooting forum for valve body replacement. There are 2 guys on there that need valve body replacement on their early model year 2023 ten speeds.

kmeleon · January 26

You have to be the first person ever to like the 8 spd over the 10 spd. Your Comment about not feeling the 10 spd shift.... That's a good thing. The 10spd is light years better than the 8.

Sean Rankin · January 26

8 minutes ago, kmeleon said:

You have to be the first person ever to like the 8 spd over the 10 spd. Your Comment about not feeling the 10 spd shift.... That's a good thing. The 10spd is light years better than the 8.

Hey man, you can make love to the 10sp if you want. I am making an observation. If I was driving a luxury car, I'd be ok with the lazy, sloppy shifts, but it's a truck. In my opinion a truck should shift like it has a pair.

Edited January 26 by Sean Rankin

garagerog · January 26

14 minutes ago, Sean Rankin said:

In my opinion a truck should shift like it has a pair.

You can use tow/haul for that.

kmeleon · January 26

35 minutes ago, garagerog said:

You can use tow/haul for that.

53 minutes ago, Sean Rankin said:

Hey man, you can make love to the 10sp if you want. I am making an observation. If I was driving a luxury car, I'd be ok with the lazy, sloppy shifts, but it's a truck. In my opinion a truck should shift like it has a pair.

You're in the minority here, the 10spd is anything but sloppy. Maybe there's something wrong with your's but the majority around here rave about it. Trucks shifting like they have shift kits are a thing of the past. Most people would prefer to not even feel the shift.

My camaro with the manual 6 speed is for banging gears.

Sean Rankin · January 26

That's what I'm looking to find out. Is my truck operating normally, or should I have it checked out. Sounds like maybe I should have it checked out if most people are happy with it.

Edited January 26 by Sean Rankin

Jay P · January 26

Unless you have the truck corrected for the 35" tires that is part of your problem. The transmission shift points were all set up using a stock size tire and a stock height truck. The tire will also mess up the ABS/Traction control/Stabilitrak. If you take it to the dealer they likely won't touch it due to the lift and bigger tires and will probably void your factory drivetrain warranty (unless the dealer sold it with the lift/tires).

FWIW the 10 speed in my past 19 Sierra 6.2l, 21 Silverado 3.0l and current Tahoe 3.0l all shift fine. I do understand the feeling of the trans shifting since I put shift kits in most of my pre electronic transmissions.

Jay

Edited January 26 by Jay P

ExYukon · January 27

I have a 2023 with the 6.2 and Max Trailering. I would describe the shifts as "smooth". Smoother than my 2001 Toyota minivan or my 6.2L 2010 Yukon.

Trotorx2 · January 27

I've had 2 2500HD's with the Allison 6 speed, one built and one with just tuning. I thought they shifted good but this 10 speed is so much better. I really like the way it smoothly goes through the gears.

typhoon186 · January 28

Smooth is the word. Almost like a variable speed. Very little change in rpm between gears. I say that is all a plus. great transmission. Probably the best every by GM.

However I would like to tune to make it feel a little more peppy and firmer for my taste.

Sean Rankin · January 28

1 minute ago, typhoon186 said:

Smooth is the word. Almost like a variable speed. Very little change in rpm between gears. I say that is all a plus. great transmission. Probably the best every by GM.

However I would like to tune to make it feel a little more peppy and firmer for my taste.

I feel the same. I've been researching to see what can be done as far as tuning goes. So far it looks like gm has the trans computer locked so that you can't tune it yet. That info is just from a brief internet search, so if someone knows more please elaborate.

Bikerjon · January 28

1 hour ago, Sean Rankin said:

I feel the same. I've been researching to see what can be done as far as tuning goes. So far it looks like gm has the trans computer locked so that you can't tune it yet. That info is just from a brief internet search, so if someone knows more please elaborate.

Following. I would like to know about tuning the trans also.