3.0 Duramax vs 6.2L V8 - which option is best?

AT4-858SD · Oct 27, 2025

I am making the move from a Tundra to the the AT4 or AT4X. I have Mercedes Sprinter that has the diesel. I'm fine with DEF and I like the mpgs that motor gets (four-cylinder). I do not tow, but I drive a lot. We also make family camping trips and pleanty of Mammouth trips in the winter. I don't plan on building out the truck and will keep it pretty much as is.

I'm on the fence about which motor to get. MPG is really important considering I've been puking money into gas in the Tundra that deson't get great mileage. I was hopign to get some feedback and opinions from folks up here that can give me some insight to both motors. What is your real-world MPG? I live in San Diego so cold weather really isn't an issue. If ya'll can let me know what you like / don't like about your motor and what you recommmend, I would greatly appreciate it.

Thanks - T

grover · Oct 27, 2025

Was originally going to go with the 6.2 until the 3.0l diesel was announced. I took one for a test ride when they first started showing up and was sold. From towing to across country trips it hasn't disappointed, I have a '20 1500 AT4. Great on fuel, very easy on Def when regular running, towing will use more of course. Summer fuel under 70mph have seen 35mpg, over 80mph mid 20's highway running. Take both out for test ride

AT4-858SD · Oct 27, 2025

grover said:
Was originally going to go with the 6.2 until the 3.0l diesel was announced. I took one for a test ride when they first started showing up and was sold. From towing to across country trips it hasn't disappointed, I have a '20 1500 AT4. Great on fuel, very easy on Def when regular running, towing will use more of course. Summer fuel under 70mph have seen 35mpg, over 80mph mid 20's highway running. Take both out for test ride

That's what I'm talking about! Thanks for your reply!

GibbyESS9 · Oct 28, 2025

I bought 2025 At4 1500 with the baby duramax last January. Love it. Mileage on 3 hour trip to vacation house I average 31 mpg st 70-75 mph. Love it can't say it enough. I drive several gmc Yukon Denalis and at4 for work and those are all gassers. First diesel for me. Def consumption very minimal, but I don't tow often. Deisel option was cheaper also.
Good luck

AT4-858SD · Oct 28, 2025

GibbyESS9 said:
I bought 2025 At4 1500 with the baby duramax last January. Love it. Mileage on 3 hour trip to vacation house I average 31 mpg st 70-75 mph. Love it can't say it enough. I drive several gmc Yukon Denalis and at4 for work and those are all gassers. First diesel for me. Def consumption very minimal, but I don't tow often. Deisel option was cheaper also.
Good luck

Thank you for the feedback!

TripleB · Oct 28, 2025

You're rolling the dice with either.

GM 3.0L Duramax Diesel Thrust Bearing Problem Causes Engine Failure, No Recall?

GM’s 3.0L Duramax diesel thrust bearing problem is causing engine failure causing GM to issue a TSB, but oddly no recall.

pickuptrucktalk.com

pigpen23 · Oct 28, 2025

If you're looking for a throw-you-into-the-seat, great passing power, throaty-sounding truck, get the 6.2L. If you're looking for better mileage and need a little more towing grunt truck, get the 3.0L.

I've had both (currently have the 3.0L), and that's about as simple as I can explain them. Love the mileage of the Babymax, but I think in the next truck I'll go back to the 6.2L for a more sport-like feel. I miss the growl of the 6.2L.

AT4-858SD · Oct 30, 2025

TripleB said:
You're rolling the dice with either.

GM 3.0L Duramax Diesel Thrust Bearing Problem Causes Engine Failure, No Recall?

GM’s 3.0L Duramax diesel thrust bearing problem is causing engine failure causing GM to issue a TSB, but oddly no recall.

pickuptrucktalk.com

Interesting! Thanks for sharing.

NorCalSixTwo · Oct 30, 2025

AT4-858SD said:
I am making the move from a Tundra to the the AT4 or AT4X. I have Mercedes Sprinter that has the diesel. I'm fine with DEF and I like the mpgs that motor gets (four-cylinder). I do not tow, but I drive a lot. We also make family camping trips and pleanty of Mammouth trips in the winter. I don't plan on building out the truck and will keep it pretty much as is.

I'm on the fence about which motor to get. MPG is really important considering I've been puking money into gas in the Tundra that deson't get great mileage. I was hopign to get some feedback and opinions from folks up here that can give me some insight to both motors. What is your real-world MPG? I live in San Diego so cold weather really isn't an issue. If ya'll can let me know what you like / don't like about your motor and what you recommmend, I would greatly appreciate it.

Thanks - T

If your main concern is MPG above all else, go with the 3.0 and don’t look back. From what I hear they excel in that department.

With that being said, the 6.2 is funner to drive, sounds better and isn’t a slouch in the towing department.

Personally, for a 1500 I’ll always opt for the “bigger & funner” gas engine & I’d only go diesel in a 2500. Since I don’t tow anything my 6.2 can’t handle, I chose to stick with it and I’m happy I did. Like someone else mentioned, you’re rolling the dice regardless. Get what suits your needs most.

pinebaron · Oct 30, 2025

NorCalSixTwo said:
Get what suits your needs most.

My wife says I tend buy whats most expensive hence she gets mad at me

. Thats not true, I like to purchase the best and its usually a little more (ok ok a lot more).

NorCalSixTwo · Oct 30, 2025

pinebaron said:
My wife says I tend buy whats most expensive hence she gets mad at me . Thats not true, I like to purchase the best and its usually a little more (ok ok a lot more).

I too have an affinity for the best stuff, just so happens to be expensive too haha

pinebaron · Oct 30, 2025

NorCalSixTwo said:
I too have an affinity for the best stuff, just so happens to be expensive too haha

LOL. I think several of you can relate to my little story below.

A couple of years ago when I was looking for a mountain bike, I think it was a day after xmas; told my wife I'm heading 150 miles to south of Seattle, to pick up a mountain bike I want and they have in stock; she wanted to come along and I said, no, you'll be arguing with me about what I may spend like $150 or more. Six hours later I returned home with the bike, a helmet, bike rack, biking gear etc. etc. I had spent $150 (00), yeah $15grand on a bike although by now I have over $20Gs in it. She was quite mad when I told her I spent $10Gs on it; heck the bike was like $13g before tax. Can't blame her really; I do this all the time with cars, trucks, motor yachts, homes etc. Its always easier to ask for forgiveness later

Several years ago, one day, at around 5pm, I told my wife and son, I need to go pick up a car I'd ordered/purchased and they came along; 40 minutes later I picked up a new Mercedes Benz (i'd paid for earlier that day) but had ordered/built/delivered from Germany, following a wait of six months; I still have that car.

My credit score is consistently 850, every month; <1% credit utilization; I must be doing something right although I'm running out of things I want (don't need).

RebelDS · Oct 31, 2025

I have gotten up to 29 with a good tail wind but normally get around 24 going 75. I can get 27-28 going 60

gemarsh · Oct 31, 2025

pinebaron said:
...although I'm running out of things I want (don't need).

Nevada is a 2A friendly State. You could always get into HK firearms. I recommend a P7M13 as your first handgun...you'll catch the bug.

You'll be in class 3 firearms in no time!

pinebaron · Oct 31, 2025

gemarsh said:
Nevada is a 2A friendly State. You could always get into HK firearms. I recommend a P7M13 as your first handgun...you'll catch the bug.

You'll be in class 3 firearms in no time!

I already have a CCP. Need some training at the range before I pick something up.