3.0L Duramax - who owns or has driven one

Nick.C · June 14, 2020

9 hours ago, topgear1224 said:

Not really,

The biggest issue I have with 3.23s is that it can't stay in 10th gear and it can't even shift into 10th gear until 70 miles an hour. at 70 miles an hour if I lock it in 9th and then change it back to automatic so it engages 10th it's the same MPG on the same road. so there's no point in having that rear gear unless you live somewhere with an 85+ mile an hour speed limit.

I maxed out my truck to 15,000 lb GCWR and it was "fine" but the exhaust brake doesn't really help that much, it's better than not having one and freewheeling down the mountain, but it's doesn't work that well when you start moving anything over 7,000 pounds. on a long 6% grade I ended up having to drag my brakes even with manual downshifting and pulling over 4200 RPM.

3.73 is much better in this regards.

Are you planning on lifting it? 3.23s already feel undergeared for the 33in stock tire size.

I finally got to drive a diesel off-road package and now I'm debating whether or not I want to take the massive depreciation hit and trade my brand new truck that I've had for 4 months in for one.

The in gear acceleration goes from being "well at least it's efficient" to "hold up did I just spin in 2nd gear???"

I call the 3L "adequate" with the 3.23 but when you have 3.73s it genuinely becomes quick.

Also the 3.73 truck really liked to ride it's torque curve versus my truck which tries to ride its torque curve and then downshifts two gears.

Fuel economy for 3.73 and 3.23 is exactly the same.
You're not going to see a real world difference unless you're setting the cruise control at 90 miles an hour.

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Thank you . You have helped me make the decision ....I will be ordering with 3.73......Just wanted to hear input from someone who drove one ...that it is worth it ....tired of hearing the Trans will make up for higher gears . I.m used to 3.73 and 4.10s in my work trucks . If a few MPG are lost ...so be it .

redwngr · June 14, 2020

20 minutes ago, Nick.C said:

Thank you . You have helped me make the decision ....I will be ordering with 3.73......Just wanted to hear input from someone who drove one ...that it is worth it ....tired of hearing the Trans will make up for higher gears . I.m used to 3.73 and 4.10s in my work trucks . If a few MPG are lost ...so be it .

What does it matter if it's in 10th?

By definition, overdrive transmissions are in 'direct' anyway.

Transmission:	10-speed 10LXX	8-speed 8LXX
Gear ratios (:1)
First:	4.70	4.56
Second:	2.99	2.97
Third:	2.15	2.08
Fourth:	1.80	1.69
Fifth:	1.52	1.27
Sixth:	1.28	1.00
Seventh:	1.00	0.85
Eighth:	0.85	0.65
Ninth:	0.69	–
Tenth:	0.64	–
Reverse:	4.87	3.82

10 speed has THREE overdrives.

Of course if taller tires than the factory offerings are a consideration....

Edited June 14, 2020 by redwngr

topgear1224 · June 14, 2020

Double post

topgear1224 · June 14, 2020

What does it matter if it's in 10th?

By definition, overdrive transmissions are in 'direct' anyway.

Transmission: 10-speed 10LXX 8-speed 8LXX

Gear ratios (:1)

First: 4.70 4.56

Second: 2.99 2.97

Third: 2.15 2.08

Fourth: 1.80 1.69

Fifth: 1.52 1.27

Sixth: 1.28 1.00

Seventh: 1.00 0.85

Eighth: 0.85 0.65

Ninth: 0.69 –

Tenth: 0.64 –

Reverse: 4.87 3.82

10 speed has THREE overdrives.

Of course if taller tires than the factory offerings are a consideration....

I think you quoted the wrong post.

Because then why did I pay for a triple overdive transmission if 10th isn't useable. I would much rather have a 1.5 gear instead. That would solve the laggy 1-2 shift due to the gear ratio spread being "hard on the drivetrain" if conducted with a 80ms shift. (GM doesn't want you chirping tires)

But that won't happen. GM nerfed the hell out of this trans. "Faster than a PDK" but for some reason they think truck drivers want slow laggy shifts.

Anywho. 3.73 increases mechanical advantage. Makes everything better. And at least in this package doesn't affect fuel economy. It's a Win-Win.

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M1ck3y · June 15, 2020

I dont understand why gm couldnt design a proper 8spd. Zf did it. There's hardly any difference in the gear spread bewteen the two. It Would have made more sense to make it a 9spd looking at those ratios.

Edited June 15, 2020 by M1ck3y

jnissen · June 15, 2020

Never had good luck with anything ZF ever touched! The 10 speed is in lots of vehicles and so far has proven to be very good.

Rubyralph · June 15, 2020

The "diesel off-road package" RPO code B4U trucks must be kind of rare, I never found one near me when I bought my 2020 truck.

Please continue to share your towing driving reviews and mpg results with the rest of us Duramax 3.0- 3.23 ratio folks.

Edited June 15, 2020 by Rubyralph
gramer

Cpl_Punishment · June 17, 2020

If the Chevy build and price website is to be believed, the diesel off road package apparently isn't available in Canada.

Benzo1 · June 23, 2020

Anyone know what GM will charge to swap out 3.23 to 3.73 including install?

ullose272 · June 23, 2020

Anyone know what GM will charge to swap out 3.23 to 3.73 including install?

I honestly would go to a drivetrain specific shop. I used to be a GM tech at a good dealer here in Boise, and we did maybe 1-2 ring an pinions a year? Id take it to someone that does them more. And you will be looking probably 2-3k

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M1ck3y · June 24, 2020

On 6/14/2020 at 8:23 PM, jnissen said:

Never had good luck with anything ZF ever touched! The 10 speed is in lots of vehicles and so far has proven to be very good.

If it was in a dodge thats because zf didnt make it. They bought the rights to produce zf products for their vehicles. Same design, made not made to the same standards.

Everyone said the same thing about the 8l90 when it came out. Gm hyped it up... Way better then the six speed, we've got it figured out now. My 8spd was amazing! Until it wasnt. But yet people trade in their crap 8spd to get a new 10spd? If this cycle keeps happening change will never happen, and we'll keep on getting whatgm wants to give us.

Edited June 24, 2020 by M1ck3y

Phatty · June 24, 2020

2020 GMC Elevation CC Standard box x31 (3.23 gears). 2500 miles now. Installed the autostopper first thing. best mod to date.
22 mpg around town taking kids to school/grocery run. 28mpg at 80mph on freeway work commutte (80 miles round trip). Best ever over 50 miles is 30.8. Both my wife and I love driving this truck, its quieter and funner to drive than our 2019 traverse (autostop, shitty 8 speed, but the wife gets what she wants...)

Towing: I have a 32 foot RV, 11 feet tall, with 6400 weight/600 tongue. GVWR 8000. (imagine 2800BH for curious) By the time we load up with all the camping gear, dog, 2 kids, bikes, etc were right at or over GVWR for trailer and max or over on towing weight, I do run a distribution hitch. But my wife takes the literal mobile home seriously and we have all sorts of useless ****** in the trailer because she might need it...

I had to put airbags on the truck after the first camping run. 3.75" of squat without them (6 pedal bikes in pickup bed). With the airbags the truck tows like a freaking dream and 0 squat. (45 PSI). Ive even found that 10psi in the bags seems to run smoother than with 0psi in them and no weight in the bed.

I live in a state with 80mph freeways and 10k foot passes and steep grades. Ive been averaging 12 mpg pulling the trailer. My 6.6 LBZ duramax never got that pulling the same RV. Ever. Wasnt even close to that. My 2014 Ram 5.7 hemi was lucky to see 8mpg.
She typically runs in 9th at 1800 rpms but always down shifts for an sort of an incline (like an overpass) at 80mph. I've pushed the truck towing to see what it can do, I wanna know its limits. She sucks the DEF fluid when towing but she doesnt back down from any grades or temps. Last weekend i pulled a long 8% grade on a state highway at 90 degrees temp (roughly 5500 ft above sea level). Tranny temps stuck at 205 and engine just above 210. She wouldnt hold 75, but tranny ran smooth and it ran over the top at 65 mph. The truck ride and performance with a trailer on is top notch and smooth.

I did find that the sweet spot for towing my RV was 70mph. It will run in 10th at 1500rpm all day with hardly any shifting and i can eek out 15-17+ mpg

Overall this is the truck I have waited years to own. Inline 6 small diesel with outstanding fuel mileage that can pull everything I really need it to. Its so quiet and smooth that my family loves riding in it, its spacious and roomy (my dog fits in the back seat with the kids, unlike my lbz or hemi crew cabs).

Things I dont like:

autostart/stop. Put the autostopper on (30 minutes to pull dash apart) and took care of that nonsense
no part numbers yet to install the bed 120v outlet of 400w. I put ebikes in the bed as well as snowmobile gear and running a boot/glove dryer on the way to my destinations is a must. Was told this came on my truck, wasnt there when i picked it up, dealer has been less than helpful in making it right.
Interior was not as nice as the ram, but the 3.0 drive and ride was much better IMO, hence I ended up with the GMC.
no wireless apple car play
cupholders are for childrens sippy cups. nalgene and hydroflask are way too big. Make some big cup holders GM. You can always buy inserts to make them smaller.
silver lug nuts on black wheels, chrome elevation badges need to go. The Ram night package is about as sexy as it gets for style. GMC needs to get it together.
24 gallon fuel tank. There is room under there for 32 gallon. give us what we want
DEF consumption while towing. She is thirsty, 3-4 hour drive towing your going to fill up with DEF somewhere along the way home.

Benzo1 · June 24, 2020

17 hours ago, ullose272 said:

I honestly would go to a drivetrain specific shop. I used to be a GM tech at a good dealer here in Boise, and we did maybe 1-2 ring an pinions a year? Id take it to someone that does them more. And you will be looking probably 2-3k

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Thanks for the feedback! I recently installed new 34" tires and have yet to tow my travel trailer. We'll see how she performs before making a decision.

Benzo1 · June 24, 2020

6 hours ago, Phatty said:

2020 GMC Elevation CC Standard box x31 (3.23 gears). 2500 miles now. Installed the autostopper first thing. best mod to date.
22 mpg around town taking kids to school/grocery run. 28mpg at 80mph on freeway work commutte (80 miles round trip). Best ever over 50 miles is 30.8. Both my wife and I love driving this truck, its quieter and funner to drive than our 2019 traverse (autostop, shitty 8 speed, but the wife gets what she wants...)

Towing: I have a 32 foot RV, 11 feet tall, with 6400 weight/600 tongue. GVWR 8000. (imagine 2800BH for curious) By the time we load up with all the camping gear, dog, 2 kids, bikes, etc were right at or over GVWR for trailer and max or over on towing weight, I do run a distribution hitch. But my wife takes the literal mobile home seriously and we have all sorts of useless ****** in the trailer because she might need it...

I had to put airbags on the truck after the first camping run. 3.75" of squat without them (6 pedal bikes in pickup bed). With the airbags the truck tows like a freaking dream and 0 squat. (45 PSI). Ive even found that 10psi in the bags seems to run smoother than with 0psi in them and no weight in the bed.

I live in a state with 80mph freeways and 10k foot passes and steep grades. Ive been averaging 12 mpg pulling the trailer. My 6.6 LBZ duramax never got that pulling the same RV. Ever. Wasnt even close to that. My 2014 Ram 5.7 hemi was lucky to see 8mpg.
She typically runs in 9th at 1800 rpms but always down shifts for an sort of an incline (like an overpass) at 80mph. I've pushed the truck towing to see what it can do, I wanna know its limits. She sucks the DEF fluid when towing but she doesnt back down from any grades or temps. Last weekend i pulled a long 8% grade on a state highway at 90 degrees temp (roughly 5500 ft above sea level). Tranny temps stuck at 205 and engine just above 210. She wouldnt hold 75, but tranny ran smooth and it ran over the top at 65 mph. The truck ride and performance with a trailer on is top notch and smooth.

I did find that the sweet spot for towing my RV was 70mph. It will run in 10th at 1500rpm all day with hardly any shifting and i can eek out 15-17+ mpg

Overall this is the truck I have waited years to own. Inline 6 small diesel with outstanding fuel mileage that can pull everything I really need it to. Its so quiet and smooth that my family loves riding in it, its spacious and roomy (my dog fits in the back seat with the kids, unlike my lbz or hemi crew cabs).

Things I dont like:

autostart/stop. Put the autostopper on (30 minutes to pull dash apart) and took care of that nonsense

no part numbers yet to install the bed 120v outlet of 400w. I put ebikes in the bed as well as snowmobile gear and running a boot/glove dryer on the way to my destinations is a must. Was told this came on my truck, wasnt there when i picked it up, dealer has been less than helpful in making it right.

Interior was not as nice as the ram, but the 3.0 drive and ride was much better IMO, hence I ended up with the GMC.

no wireless apple car play

cupholders are for childrens sippy cups. nalgene and hydroflask are way too big. Make some big cup holders GM. You can always buy inserts to make them smaller.

silver lug nuts on black wheels, chrome elevation badges need to go. The Ram night package is about as sexy as it gets for style. GMC needs to get it together.

24 gallon fuel tank. There is room under there for 32 gallon. give us what we want

DEF consumption while towing. She is thirsty, 3-4 hour drive towing your going to fill up with DEF somewhere along the way home.

Great Review! Couple questions as I also have a 3.0L Duramax and tow a trailer of similar weight...

What Airbags did you go with?

When running 10psi how much different is the ride compared to without the airbags?

And BTW - love the Imagine Trailers. Looking to sell our current ToyHauler and get a new Imagine as well...

ullose272 · June 24, 2020

Thanks for the feedback! I recently installed new 34" tires and have yet to tow my travel trailer. We'll see how she performs before making a decision.

Got any pics? How much lift?

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