Transmission Holding Lower Gear After Moderate to Hard Acceleration

[WalleyeMikeIII]

Hi all, started noticing my Yukon XL w/ the 6.2L "holding" on to a lower gear after downshifting during a moderate to hard acceleration.
I am not sure if I just noticed this and it has always been doing it, or if it is a new phenomenon.

It still shifts smoothly in normal driving, but if I give it a litte gas (like to pass a vehicle on a 2 lane highway) that causes a downshift of a few gears...when I immediately let off the accelerator, it seems to hold the lower gear, and begin to slow down.
If I don't let all the way off the accelerator, it will happily upshift to one of its higher gears and get the RPM's back to ~1200 range.

Steps to make it happen.
1) Be driving along at 35 MPH or more.
2) Mash the gas half way or more, vehicle downshifts and gets going (with a smile and a fun growl), get it up to 55-60 MPH.
3) Release the accelerator
4) Transmission seems to stay in the lower gear, and if no more accelerator applied, will stay in this lower gear, and slow due to engine, not shift to a higher gear and coast.

Applying even a slight press of the accelerator after #4 above and it will upshift to a higher gear.

It feels to me like this is a new thing, I don't recall this in the first 28,000 or so, but in the last 1200 miles I have noticed it. Perhaps it was always this way, and I noticed it and became sensitive.

Anyone else experience this? Is it normal? I am about due for an oil change, and will ask the dealer about it when I go in, but thought I would poll the group to see your experience.

 

[B-train]

I've noticed this in my 2008 and 2017 from time to time. I don't know what causes it, other than maybe a torque management strategy in the ECM that thinks you are all of a sudden in fast and furious mode? It's either a safe guard feature, or a confused ECM not knowing what it's supposed to do next with its life after being startled from it's slumber at 35 mph.

 

[swathdiver]

It does learn and adapt to your driving style, maybe that's why.

 

[iamlegion]

Probably torque management kicking in to protect the transmission. When it holds the gear does it require a stab of the throttle to let go? If you just coast does it upshift on its own?

 

[WalleyeMikeIII]

Probably torque management kicking in to protect the transmission. When it holds the gear does it require a stab of the throttle to let go? If you just coast does it upshift on its own?

No. Just coasting holds the lower gear. Need to lightly apply throttle to affect an upshift.

 

[Marky Dissod]

Probably torque management kicking in to protect the transmission.
When it holds the gear does it require a stab of the throttle to let go?
If you just coast does it upshift on its own?

No. Just coasting holds the lower gear. Need to lightly apply throttle to affect an upshift.

Actually, it's very nice of the geartrain to wait for your input.
What they used to do was assume you wanted the highest (laziest / least enthusiastic) gear possible.

 

[KMeloney]

I have noticed this a couple times lately in my '23 Denali (w/just under 9K on it). I think I've noticed it on some occasions around 25-40 mph. It's definitely not an "all the time" thing, but I'm betting it's the same thing you're experiencing. Can't say exactly what brings it on, so I'll be following this thread.

 

[WalleyeMikeIII]

Update: had the Yukon at the dealer for this, Master Tech drove it w/ diags system connected. No issues noted, said this is how it is designed...holds low gear, does not upshift without any throttle input. Perhaps indeed it has been this way from the beginning and I just didn't notice it. I am ok w/ this type of operation, now that I know how it works...leaves the power in my foot if i want it again.

 

[89Suburban]

@NickTransmissions thoughts?

 

[NickTransmissions]

@NickTransmissions thoughts?

I have nothing to add to post 8, sounds normal to me but I'm not familiar w/these newer 10-speed units.

Here are the symptoms people want to watch out for and take action if observed:

1. Shuddering at any speed/gear/range position
2. Slipping
3. Delayed Engagements
4. Wrong gear starts
5. Missing gears, skipping gears
6. Flare Shifting
7. Tie ups and/or binds
8. Grinding noises coming from the transmission
9. Transmission overheating
10. Transmission inexplicably expelling fluid from the vent tube or leaking
11. No forward and/or reverse movement
12. Limp mode (only certain gears available)
13. No upshift from first gear
14. Clunky, jerky, bumpy, harsh or overly soft shifts
15. Any variation or similar symptom to any of the above

 

[jerry455]

My 21 Suburban will do that but I put it in sport mode quite often. I like how the suspension stiffens and the shift points are a little more aggressive.

 

[viven44]

I've observed this behavior on other 8 / 10 speeds in Sport mode.... will need to pay more attention (if and when I ever drive our 2024!) if this happens in normal mode on the GM 10 speed.

 

[TrueAt1stLight]

My 21 Suburban will do that but I put it in sport mode quite often. I like how the suspension stiffens and the shift points are a little more aggressive.

The suspension stiffens? @jerry455 I could be wrong but I’m not aware of our vehicles having adaptive suspensions in sport mode. I have an 24’ AT4 XL with air ride suspension and never heard of this.

 

[KMeloney]

The suspension stiffens? @jerry455 I could be wrong but I’m not aware of our vehicles having adaptive suspensions in sport mode. I have an 24’ AT4 XL with air ride suspension and never heard of this.

In my '23 Denali, the suspension lowers in Sport mode (and the steering feels tighter, at least on the highway).

 

[jerry455]

I don't have air but the electronic shocks or magnaride, are supposed stiffen. This is from the owners manual for my 2012 Suburban:
Sport Mode
Use where road conditions or personal preference demand a more controlled response. When you enter this mode you will immediately feel a down shift. In this mode, the vehicle also monitors driving behaviors and automatically enables Performance Shift Features when spirited driving is detected. These features maintain lower transmission gears to increase available engine braking and improve acceleration response. The vehicle will exit these features and return to normal operation after a short period when no spirited driving is detected. The steering will change to provide more precise control. If the vehicle has Magnetic Ride Control, the suspension will change to provide better cornering performance.

 

[jerry455]

I don't have air but the electronic shocks or magnaride, are supposed stiffen. This is from the owners manual for my 2012 Suburban:
Sport Mode
Use where road conditions or personal preference demand a more controlled response. When you enter this mode you will immediately feel a down shift. In this mode, the vehicle also monitors driving behaviors and automatically enables Performance Shift Features when spirited driving is detected. These features maintain lower transmission gears to increase available engine braking and improve acceleration response. The vehicle will exit these features and return to normal operation after a short period when no spirited driving is detected. The steering will change to provide more precise control. If the vehicle has Magnetic Ride Control, the suspension will change to provide better cornering performance.

Sorry, 2021 Suburban.

 

[Sean Michael]

I don't have air but the electronic shocks or magnaride, are supposed stiffen. This is from the owners manual for my 2012 Suburban:
Sport Mode
Use where road conditions or personal preference demand a more controlled response. When you enter this mode you will immediately feel a down shift. In this mode, the vehicle also monitors driving behaviors and automatically enables Performance Shift Features when spirited driving is detected. These features maintain lower transmission gears to increase available engine braking and improve acceleration response. The vehicle will exit these features and return to normal operation after a short period when no spirited driving is detected. The steering will change to provide more precise control. If the vehicle has Magnetic Ride Control, the suspension will change to provide better cornering performance.

This got me curious about my 2024 RST with Magnaride so I checked the manual and did not see the same reference to Sport Mode changing Magnaride"to provide better cornering performance". Either they've changed the Sport Mode setting parameters between 2021 and 2024, or just changed what's printed in the owner's manual.

No big deal IMO, this is my 3rd Tahoe but first with Magnaride, and it all around handles so much better than my previous Tahoes that I'm happy with how it performs all around regardless. I don't know how much of that is attributed to the independent rear (my prior Tahoes were previous gens with solid rear axle) or how much is attributed to this one being my first with Magnaride. I don't expect 5,700lb trucks to necessarily feel sporty, but this 6.2L with Magnaride feels pretty dang sporty for what it is.