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2023 L8T 10 Speed

C/K Man

By C/K Man
in 6.6L Gas V8 (L8T)

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rileyc Enthusiast

rileyc

Posted
Posted

I have always owned Chevy trucks, and I am looking to purchase a new one-ton gasoline powered pickup for hauling a truck camper.  I have spent a lot of time researching all the major manufacturers:  Ford, GM, and RAM.  Each brand has some advantages as well as disadvantages in terms of technology, reliability, and performance.  

 

The new GM L8T 6.6L engine appears to have some early release issues which, hopefully, GM has/will correct.  I like both the horsepower and available torque from this engine.  I further like the simple, robust design of a cam-in-block truck engine, and I am glad GM did away with AFM for this engine.   

 

Regarding the 6L90 transmission, it's reliable, but both Ram and Ford offer 8 and 10 speed transmissions respectively in their one-ton trucks.  To me, the 6L90 is outdated when compared to the competition.  I do understand Ford has/is having some release issues with the 10R140 transmission which they are now working through the problems.  Ram uses a ZF 8HP75-LCV which has a good track record, and RAM is a strong candidate for my business.

 

Not only does GM need an updated transmission with the L8T engine, they need to offer a 4.10 rear axle as well.  In my opinion, having a 10 speed transmission and the option of a 4.10 rear axle would help level the playing field.  

 

I like Chevy trucks; so, I am willing to wait to see if GM is going to make a 10 speed transmission available for the 2023 model year.  If not, I may be buying my first non-GM heavy-duty truck.  

 

   

 

 

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Epsilon Plus
Epsilon Plus

I wouldn't be surprised to see it in LTZ or higher trims, or maybe even a stand alone option for LT, perhaps included with LT. Reason being is the 6L90E is the bulletproof fleet trans on the market. I

SWDoodle
SWDoodle

I would be fine with 4.10/4.30’s with the 6-speed.  I just don’t understand why GM won’t give some options for Max payload with the gas.  I would agree the 10 speed may shift a ton if towing.  You’d a

Epsilon Plus
Epsilon Plus

Read between all the lines of this thread and you'll find if you're the average home owner/truck guy not needing to tow more than 10,000lbs with a travel trailer or dump trailer/equipment trailer then

  • 3 months later...
MacLaren Enthusiast

MacLaren

Posted
Posted (edited)

I'll take this ole bullet proof 6 speed any day. I love it. Imo, this is the very best 2500 gasser on the market by a long shot too. All things considered. 

Cast Iron Block, Stainless Crank, Beefed up 6 speed tranny, huge radiator, - and there's no doubt these babies will pull. And the mpg is just outstanding. I get 16-18 when not towing. And, I live in the mountains. 

I've rode in the Godzilla. It's speed is impressive. No doubt about it. But, the mpg is just horrendous- no doubt about that either. Nah, I don't want this big boy searching for gears all the time. Gas mileage is good enough imo. 

Ya know these trucks are so deceiving- just regular driving would lead one to think she's not that strong....thats until hook her up to tow.....

Edited by MacLaren
  • Like 1
sheath Enthusiast

sheath

Posted
Posted

I'd like to see a gear to split the ratio between L2 and L3 with converter lock-up.  Also L1 to L2 is a big gap, and could use a gear there.

 

My experience towing heavy (14,300 lbs to 15,000 lbs) is that the L8T makes it's best power above 4.2K rpms.   I prefer to drive in the 3,500-4,200 rpm range, but below 4,200 rpm under heavy load the engine falls on its face.  That is really limiting with the 6 speed because of the huge gap (almost 1,500 rpm) between L3 and L2.  So it downshifts from about 3,800 rpm to over 5,200 rpm.   I hate to push that high rpms under heavy loads when climbing long grades, and the lack of torque converter lock-up in L2 creates really high transmission temperatures.

The downshift clunk we feel intermittently at low speed between L2 and L1 would be greatly diminished with a gear to split that ratio as well.

Originally I was happy with the 6L90E, but the more I drive (about 14,K miles with just under 30% towing heavy), the more I'd like a strong 8 speed, or even 10 speed if it didn't negatively impact the fuel mileage.

 

Maybe keep the 6L90E as standard (help keep fleet costs reasonable), and offer the 8 or 10 speed as an option. I'd like to see that option with a rotary PRNDL on the dash, a paddle shift for manual shifting on the steering wheel, a "gear lock" function in tow haul mode to keep the transmission from automatically downshifting under load and an actual gear indicator display on the dash that shows what gear the transmission is actually in. 

If the option was under $3K MSRP, I'd order it.  Actually I'd seriously consider trading in my '22 for that.

SWDoodle Enthusiast

SWDoodle

Posted
Posted
9 hours ago, sheath said:

I'd like to see a gear to split the ratio between L2 and L3 with converter lock-up.  Also L1 to L2 is a big gap, and could use a gear there.

 

My experience towing heavy (14,300 lbs to 15,000 lbs) is that the L8T makes it's best power above 4.2K rpms.   I prefer to drive in the 3,500-4,200 rpm range, but below 4,200 rpm under heavy load the engine falls on its face.  That is really limiting with the 6 speed because of the huge gap (almost 1,500 rpm) between L3 and L2.  So it downshifts from about 3,800 rpm to over 5,200 rpm.   I hate to push that high rpms under heavy loads when climbing long grades, and the lack of torque converter lock-up in L2 creates really high transmission temperatures.

The downshift clunk we feel intermittently at low speed between L2 and L1 would be greatly diminished with a gear to split that ratio as well.

Originally I was happy with the 6L90E, but the more I drive (about 14,K miles with just under 30% towing heavy), the more I'd like a strong 8 speed, or even 10 speed if it didn't negatively impact the fuel mileage.

 

Maybe keep the 6L90E as standard (help keep fleet costs reasonable), and offer the 8 or 10 speed as an option. I'd like to see that option with a rotary PRNDL on the dash, a paddle shift for manual shifting on the steering wheel, a "gear lock" function in tow haul mode to keep the transmission from automatically downshifting under load and an actual gear indicator display on the dash that shows what gear the transmission is actually in. 

If the option was under $3K MSRP, I'd order it.  Actually I'd seriously consider trading in my '22 for that.

 

Thats the dilema I'm in right now.  Wait for a 2024 with the new 10 speed or get a leftover 22/23 with the 6 speed.  I would bet the 10 speed will be an upgrade while the 6 speed will stay in the WT/Pro lineup for fleet buyers.  I just hope it's not a big jump to the transmission and they offer a 4.10.  That might be a good setup and help with the guys who tow towards the top end.  I would be in that category.  I would have flatbed trailers with a GCW of 14-16K.  I know that's diesel territory but I only tow seasonally and live in flat country.  I'm keeping my LML but looking at a second HD to help me when times are busy. 

Ray Pickle Enthusiast

Ray Pickle

Posted
Posted

Couple of comments hear desiring 4.10 gear along with 10 speed. Frankly the need for 4.10 is greater now with 6 speed. 10 speed has deeper gearing and the benefits of lower axle ratio are greatly reduced, not to mention poorer mpg of lower gear offsetting potential gains from trans.

newdude Senior Enthusiast

newdude

Posted
Posted
19 minutes ago, Ray Pickle said:

Couple of comments hear desiring 4.10 gear along with 10 speed. Frankly the need for 4.10 is greater now with 6 speed. 10 speed has deeper gearing and the benefits of lower axle ratio are greatly reduced, not to mention poorer mpg of lower gear offsetting potential gains from trans.

 

 

Yes.  They should have kept the 4.10 with the 6 speed like they paired them from 15-19.  When I saw GM announce 3.73s I was sure that it was with the 10 speed but then they said 6 speed and it was a WTF moment.  

Doodle Enthusiast

Doodle

Posted
Posted
22 hours ago, Ray Pickle said:

Couple of comments hear desiring 4.10 gear along with 10 speed. Frankly the need for 4.10 is greater now with 6 speed. 10 speed has deeper gearing and the benefits of lower axle ratio are greatly reduced, not to mention poorer mpg of lower gear offsetting potential gains from trans.

You’re probably right on that, the 3.73 would likely be adequate but I”m sure GM will do something stupid and do like 3.23 with the 10 speed.  We have a Yukon with 3.09’s and a 6 speed and it will downshift on any incline.  

Doodle Enthusiast

Doodle

Posted
Posted
22 hours ago, newdude said:

 

 

Yes.  They should have kept the 4.10 with the 6 speed like they paired them from 15-19.  When I saw GM announce 3.73s I was sure that it was with the 10 speed but then they said 6 speed and it was a WTF moment.  

At the least have made the 4.10’s an option.  That’s what I had in my 2005 and it worked good even with a 4 speed.  

  • 1 month later...
Bigaustino Enthusiast

Bigaustino

Posted
Posted

I must be the only person on the planet who dreams of a 6 speed with a third pedal and 4.10 gears in one of these new trucks. Would love to buy a gas dually to replace my 2500hd 6.0 as I will never own a diesel and have sadly been considering a ford 7.3 4.30 dually. 

sheath Enthusiast

sheath

Posted
Posted

Nothing wrong with a Ford.  That is a darned nice truck! :cheers:

(but the Chevy is better... 😉)

Another JR Senior Enthusiast

Another JR

Posted
Posted
23 minutes ago, MTU Alum said:

It's officially out.  2024 L8T with 10 speed and 3.73 rear axle.

 

#IworkforGM

As an option or are they only offered in 10 speed?

C/K Man Enthusiast

C/K Man

Posted
  • Author
Posted

And it looks like it is the 10L1000.  I figured it would be, the 10L90 is the sister of the Ford 10R80, and Ford does not use that transmission in the Super Duty.   

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