Concerns with 6 speed transmission vs 10 speed transmission?

[Gabe Bunn]

I have currently built 2 different GMC SLE 2500's. Both are equipped the same but one has the diesel and the other has the new 6.6 gas motor. I know the Duramax comes with the 10 speed transmission and the gas has the 6 speed transmission. There's about $8,000 difference in price with me getting Friends and Family pricing. I can get along fine with the gas for my needs, I'm just wondering about the transmissions between the 2. I'll keep the truck 7-8 years like I normally do. Just trying to get a truck as economically feasible as possible. I've had diesels in the past but I only have a bumper pull camper and a pontoon boat now so I know the gasser will pull them both with ease. Is the different transmissions and motors worth the $8K over how long I'll keep the truck? Just don't want to be stuck with the 6 speed transmission if it isn't really reliable.  THANKS

[Wxman]

Reliability with the six speed would not be a concern with me.  The transmission has been around a while and is pretty much considered bullet proof as far as I know.  One could argue advantages or disadvantages of more gears, rpm ranges, fuel mileage, etc., but I wouldn't worry about reliability.

I pull a fishing boat and a 10K lb RV and have been very satisfied.

[CRApex]

I believe there is a recall on 6spd transmission cooler lines.  We had issues with two of our 6.6 gas trucks, one of which required replacing the transmission.  Other than that, I think they're fine.  Now don't get me started on how much better the towing and driving experience is with the diesel and 10spd.  Discussions like this always seem to get strong opinions one way or the other.

[Ray Pickle]

Lowest warranty transmission over time has been the 6 speed in h.d. trucks I would assume that will continue based on additional enhancements made in 2020 additional clutches etc.

[Another JR]

I am very happy with the performance of the gas engine and 6 speed transmission.
 

My truck was delivered last April, and the transmission cooler line recall does not apply to it. I hope that’s because they used the improved parts rather than lack of enough parts for the newer trucks. 

[Gabe Bunn]

The cooler line was one of my concerns. Is the transmission in the 2500’s the same as the transmissions in the 1500’s? Just wondering if they “beefed” up anything in the transmission for the 3/4 tons over the 1/2 tons. Thanks for the replies 

[L8T]

55 minutes ago, Gabe Bunn said:

The cooler line was one of my concerns. Is the transmission in the 2500’s the same as the transmissions in the 1500’s? Just wondering if they “beefed” up anything in the transmission for the 3/4 tons over the 1/2 tons. Thanks for the replies 

They are nothing alike. More accurately they are a heavier built updated version of the 6 speed that came behind the previous 6 liter trucks. Reliability is probably their strongest plus. 

[MORSNO]

On 9/23/2021 at 9:39 PM, Gabe Bunn said:

The cooler line was one of my concerns. Is the transmission in the 2500’s the same as the transmissions in the 1500’s? Just wondering if they “beefed” up anything in the transmission for the 3/4 tons over the 1/2 tons. Thanks for the replies 

 

They are not even close to being the same.  The HD truck transmission is built like a tank and has proven itself for many years.  Mine has been hauling a 3,200 truck camper all over Alaska, Canada, and the Northwest US for nine years. 

[CRApex]

Just saw this note in an article published by GM Authority.  Speaking to the 2023 and newer trucks.  They mention the new updated truck has been pushed to 2024 due to Covid supply issues so would assume the 10spd won't be available until the 2024 model year.

 

"Additionally, the GM 10-speed automatic transmission is expected to replace the six-speed auto in models equipped with the atmospheric 6.6L V8 L8T gasoline engine, which is rated at 401 horsepower and 464 pound-feet of torque."

 

https://gmauthority.com/blog/2021/10/2023-silverado-hd-dually-reveals-new-grille-front-end-design/

 

[pokismoki]

the 6L90 is stout , the only one with issues are the 1500 trucks with the 6L80. if you got a 2500 truck, they have all the upgrades and updates installed so no worries

Edited October 20, 2021 by pokismoki

[pokismoki]

10 speed is new and might have bugs and glitches, it has more rotational mass than a 6l90, so it will rob you of HP and consume more fuel, not to mention rebuild cost will be astronomical  compared to the old 6 speeds

[Polo08816]

On 10/20/2021 at 9:48 AM, CRApex said:

Just saw this note in an article published by GM Authority.  Speaking to the 2023 and newer trucks.  They mention the new updated truck has been pushed to 2024 due to Covid supply issues so would assume the 10spd won't be available until the 2024 model year.

 

"Additionally, the GM 10-speed automatic transmission is expected to replace the six-speed auto in models equipped with the atmospheric 6.6L V8 L8T gasoline engine, which is rated at 401 horsepower and 464 pound-feet of torque."

 

https://gmauthority.com/blog/2021/10/2023-silverado-hd-dually-reveals-new-grille-front-end-design/

 

 

They should try to make it 2023.  I think Ford is going to revise the Super Duty for 2023.  It would be nice to be able to have a vehicle with the same launch year so they don't lose all those sales to Ford.

 

And it's about time for a 10 sped automatic for the gas engine to compete with Ford's 7.3L V8 + 10 speed combo.

Edited October 22, 2021 by Polo08816

[CRApex]

1 hour ago, Polo08816 said:

 

They should try to make it 2023.  I think Ford is going to revise the Super Duty for 2023.  It would be nice to be able to have a vehicle with the same launch year so they don't lose all those sales to Ford.

 

And it's about time for a 10 sped automatic for the gas engine to compete with Ford's 7.3L V8 + 10 speed combo.

Totally agree.  Yes, the 6spd is good for what it is but I won't even consider the gas motor until the 10spd is an option.

[Ray Pickle]

I won't consider a new truck until they offer a 15 speed! Lol. How in the world did we ever survive with those old THM350 and 400 transmissions back in the dark ages. C'mon folks a 6 -8- or 10 speed in a gas engined truck that operates best between 2 and 5k rpm have very small practical comparative operating differences. Evidenced by performance of F250 with 7.3- 10 speed equipped with 3.73. (Not4.10)

[CRApex]

19 hours ago, Ray Pickle said:

I won't consider a new truck until they offer a 15 speed! Lol. How in the world did we ever survive with those old THM350 and 400 transmissions back in the dark ages. C'mon folks a 6 -8- or 10 speed in a gas engined truck that operates best between 2 and 5k rpm have very small practical comparative operating differences. Evidenced by performance of F250 with 7.3- 10 speed equipped with 3.73. (Not4.10)

With that logic just keep it simple and go back to a 4spd..lol.

 

Sorry, I'll stick with my statement...until they offer a 10spd, I won't consider the gas truck..and even then I still might prefer the diesel but atleast it will make me think about it.