Which dually - 8.1 vs pre-DEF 6.6?

[bucket]

I'm not sure, but there are loads of them around still.

Someone i know got some off amazon and hasn't ran into any issues yet. It's been like 6 months on those plates.

When I last looked into it, it was like 6 months from going into effect and the local hardware store had all the farm plates on clearance, lol. They were marked down to like $1.99 or something. I thought they used to be around 10 bucks.

 

[Frankenchevy]

This is not even a debate, Dmax period end of any gas motor nonsense for towing... If you're going to tow anything heavier than a moped gassers SUCK anyone who tells you otherwise has never towed with a Dmax, Powerstroke or Cummins... Not to mention the vast tuning options with the Dmax, toss a 120hp non delete tune in it you wont even know that camper is behind you and that's from experience...

A lot of fleets are switching back to gassers due to diesels having higher initial costs and significantly more expensive maintenance. Towing a dump trailer, not a camper. FWIW, I’ve towed equipment and dump trailers with a 5.3 in a 1500, just not with a big block.

If you’re not doing daily work with it, I’m not certain what you could possibly do with a dump trailer that your 3rd gen wouldn’t handle just fine. Don’t even need a dually unless you have a GN trailer and GN pin weights. Which the 3rd gen will still handle over 4k of pin weight easily.
If you are using it regularly and highway speeds/mountains, the 8.1 makes sense to me other than it’s cheaper than a diesel. Otherwise a LLY or LBZ will walk a 8.1 easily with a trailer. And a small tune and it’ll absolutely destroy the 8.1 but not the Allison.
Idk why the 8.1 is even a consideration unless infrequent use.

It is intended to be a work truck. My 04 Cummins will be primarily to tote around my slide in truck camper and my 2020 Laramie Longhorn is my cowboy Cadillac and only my wife and I are allowed to drive it. This truck will be for others to use for work related purposes. A dually gives me more option for the future.

 

[Grit dog]

Oh, employee-mobile? Got a gmt900 6.0 duallly. They’re basically indestructible and dumb **** proof and newer than the 800s, hypothetically a bit better.
Who cares if it’s slow and eats brakes on the the hills. You’re paying them by the hour. An 8.1 will too although I’d rather have the Alli trans. So maybe a toss up. As long as the 8.1 doesn’t drink oil. = bad feature in an employee-mobile. I never check the oil in my company truck, lol. Unless Jippo Lube pulling the dipstick every 3-4 months during an oil change counts!
I thought you wanted something for YOU to tow with. Who cares if the engine is screaming in Jose’s ears…..

 

[Grit dog]

Honestly if I was looking for the best bang for buck in a reliable gasser dually, the Ford V10 (5 speed auto not 4 speed) or 6.2 6 speed would be on my short list.
And I don’t even like Fords!

 

[Frankenchevy]

Honestly if I was looking for the best bang for buck in a reliable gasser dually, the Ford V10 (5 speed auto not 4 speed) or 6.2 6 speed would be on my short list.
And I don’t even like Fords!

A lot of guys are liking the 7.3 Godzilla gasser. I’d consider one of those if the price was right. Talked to a tranny shop and the said the 10-speeds seem pretty decent so far.

 

[Grit dog]

A lot of guys are liking the 7.3 Godzilla gasser. I’d consider one of those if the price was right. Talked to a tranny shop and the said the 10-speeds seem pretty decent so far.

I haven’t seen any issues with the 6.8 and 7.3 V8s in our trucks but they’re all pretty new low miles.
I don’t think GM or Ford 10 speed HD trans are issues. Half tons either. Half tons are actually same trans Ford or GM. And with Ram having versions of the 8speed ZF now in all trucks including new diesels, there isn’t a suspect trans in the big 3 lineup anywhere.
I was thinking in the cheaper used budget range with the 6.2 or V10 reccomendation.

 

[Hunter79764]

No experience with the Duramax, but I've got an 8.1 in my motorhome and love it. It's a class 5 Kodiak based unit, weighed on our last vacation riiiiight at 26k total with my 87 K20 suburban flat towing behind. It was trying a bit on the long uphill passes through the Rockies, but overall, was fine. I'm happy enough with it that I easily recommended one for my dad, who is looking for a lighter tow vehicle (3/4t or maybe 1T SRW) for 10k max. I've got a 6.0 that I wouldn't care for in a tow truck but I'm sure would do the job.

As far as oil, I burn about 1 quart in 2k miles, sometimes more, sometimes less, although I think I'm using less overall since I put in a 180° t stat but not confirmed. I just run standard dino oil and a large filter, in the medium duty chassis its a 10 qt pan and "Low" mark is 3 qts low, I change it at 4-5k (usually do that in a year, so I change in the spring usually). Best MPG was almost 8, lowest is ~5.5 mpg. Trip from Texas to the Grand Canyon, through Utah, and back with some generator usage hurting MPG was just above 6 mpg on 3500 miles, but 12' high, 8' wide, and 35' long with a 6k Suburban behind it. Kodiak 8.1's were de-tuned from the factory, I believe, but around town and normal driving, I've never felt power/torque limited. Long uphill grades made me wish I had a tune or something, but not unbearable.
If they came with the 6 speed Allison in later years, that might be a useful upgrade if fuel consumption is a concern. I suspect I'd gain about 1 mpg with the 6 speed based on the instant change from 5th to 4th to 3rd.

 

[TotalyHucked]

A lot of fleets are switching back to gassers due to diesels having higher initial costs and significantly more expensive maintenance. Towing a dump trailer, not a camper. FWIW, I’ve towed equipment and dump trailers with a 5.3 in a 1500, just not with a big block.

It is intended to be a work truck. My 04 Cummins will be primarily to tote around my slide in truck camper and my 2020 Laramie Longhorn is my cowboy Cadillac and only my wife and I are allowed to drive it. This truck will be for others to use for work related purposes. A dually gives me more option for the future.

Was gonna chime in here and ask what the usage was before giving recommendations. But seeing as it's an employee mobile, I would definitely go 8.1.

The LB7s and LLYs (01-03 and 04-early 06) are great engines but thanks to the injector issues, they need a conscious owner to keep up with them. Fantastic trucks, I had an '03 GMC with the LB7. Other than needing injectors (white haze out the exhaust), it was a great truck. 4x4, CCSB, leveled on 33s but only got 14 no matter what.

My buddy has an '03 GMC CCSB 4x4 with an 8.1/allison and LOVES it other than the 8mpg. But you can dump regular fuel in it, just keep the oil changed and it'll move anything you ask of it. Just slower than a Dmax. I told him I wanna buy it from him if he ever sells it.

 

[bucket]

Yes, the 8.1's are somewhat detuned in factory form. Tuning them is supposed to be good for 400-420 HP and 500 or so TQ, from what I have read.

 

[TotalyHucked]

One of our guys at work swapped an 8.1/4L80 into his squarebody dually 'burb. Should be done soon, I'm curious to see how he likes it

 

[bucket]

One of our guys at work swapped an 8.1/4L80 into his squarebody dually 'burb. Should be done soon, I'm curious to see how he likes it

I'll be curious too. I've got to get started on swapping mine, although with a manual trans.

 

[Frankenchevy]

There is a video I watched where a shop did the intake mod (apparently there’s a restriction that can be fixed with a small bit of welding). While they were at it the installed a cam and did some tuning. It liked a bit more timing on standard octane, but showed no improvement when they tuned for premium and bumped up the timing. His hypothesis was that the factory throttle body was the restriction at that point.

I’ll see if I can find the video. They put it against a similar era dmax.

 

[Frankenchevy]

Cam video:

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Tow video maxxing out gcwr & gvwr/gawr:

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