Anyone out there have one and have anything good or bad to say about it? With GM allowing you to mate the 10 speed allison on the 2024 models, I am seriously contemplating ordering a 2500 sierra.

For my use, a gas 3/4 ton will tow more than I need, just the idea of a large V8 and a premium transmission is appealing as far as limited maintenance concerns and longevity/reliability (compared to Deisel and hybrid trucks)

I have just over 3000 miles on the new ranch truck. Love the 6.6 engine and a few other little things about the truck, but overall there is more I don't like. Give me a Ford with a 6.2, or better yet, a 7.3 gasser over the GM any old day....... The ford is more 'user friendly'.

I have about 15,000 miles on my 2500HD. I had a Ford 6.2 and I like this 6.6 engine better. Feels like it makes more power at a lower rpm. The 6.2 just seemed like a much higher revving engine.

A 10 speed Allison behind it would be sweet.

I have about 9300 miles on my ‘22 and love it so far. Lots of power for what I use it for and tow. No issues at all yet. Rides nice. The 10 speed Allison would be nice touch I think and really add to the truck’s performance.

I am currently running a highly tuned Duramax in a 2500 HD and love it, but I want to add a 3/4 ton gasser to the stable in the form of the anticipated ZR2 package that is rumored to become available later this year.

Waiting to see what develops...

I’m at 30,000 on mine. The engine is noticeably stronger than the old 6.0, tows great, and gets slightly better mileage than the 6.0. That being said, I’m scheduled for an oil consumption test this week. It has gone through more oil lately than I think it should, and GM has a protocol to test for that. It may just be the nature of a DI gas engine, I don’t know.

How much is it using?

Would be interested to hear the results of the test.

I’ll let you know. It takes a while as it is a function of fuel consumed. I haven’t paid attention to mileage, but it was low about 700 miles after an oil change. They probably didn’t fill it up correctly, so I did. Since that time on the same oil change it has used a quart with almost no towing involved. I have an appointment tomorrow morning.

They start with a fresh oil change and verify that it is full. Then you track fuel consumed and oil used for X amount of fuel and miles. They have some limit they deem acceptable. I think it is a quart per 100 gallons of fuel. That works out to a quart per 1,000 to 1,300 miles at the mileage I get. Seems like a lot of oil to me. I believe the limit on the Duramax is the same. When it’s done I’ll try to remember to post here.

I’ve had a Duramax and a 6.0 and neither used any appreciable amount of oil.

Seems like a lot of oil, it is.

Years ago I complained to Madmooner's Dad about the oil consumption in a
vehicle I drove, he worked on its design.
He explained that it was exactly where they wanted it, too little oil getting past the
oil ring wears out the compression rings.

If a 30 year old memory is to be trusted, he was liking 1/2 cup per thousand.
In a much harder working engine.

Yep. We will see how it goes. I am hoping it either uses nothing or over the limit. None of this 0.75 quarts in 100 gallons is ok stuff.

This is your friend. Keeps from deactivating cylinders,dumb idea that engineers know can lead to oil consumption.

https://www.rangetechnology.com/products/afm-dfm_disabler/

I used to worry about a 5.3 I had using a quart every 1200 miles or so but once it burned that 6th quart up it used hardly any, almost like 6 quarts was too much. Like dad says, burning some oil just means things are getting lubricated.

The new owner just changed the 2nd set of plugs that engine has had, right at 250k on the odometer right now. Never fouled a plug, no clue where that oil went.

The 6.6 doesn’t have AFM.

👍🏻👍🏻

Oil sucked in from the ri gs and burns well. Clean.
Oil leaking around valve seals doesnt,you get smoke and carbon..

What I've always been taught anyways.

Not sure what's going on in that blue cloud producing POS I get behind!

I'm at 12,000 miles with my 2022 6.6. Vast improvement in towing over my previous 6.0. Generates much more torque at lower rpms. No oil issues as of yet. Only wish I had that 10 speed Allison.

I have a 2500 work truck with tool box bed it has 14000 miles, its good so far and im getting12 mpg daily driving in the mountains. It is not the same power or torque as my 06 duramax but its great so far.