Might Be Getting Gassed

LBZ

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Jul 2, 2007
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So the lml isn’t really on my required list right now since I sold my toy hauler and at 150 000km it’s already starting to show black truck issues - mostly in the rock chip department. It pretty much needs a full paint job, bumper on the front replaced along with the grille. Western Canada roads have been very hard on it. And being black doesn’t help.

So I’ve been looking at the new 6.6 gasser 3500HD trucks and am leaning towards a new Denali. Talked to the local dealer and got a quote from an exporter that will ship the truck to the states to sell and is willing to give me 45k for the truck as is. So I’m even more tempted now to just walk away from it before it starts nickel and diming me to death with maintenance costs and the ticking time bomb cp4.

So how many of y’all on here have had anything to do with the new gasser? How are they for comfort and reliability compared to the old 6.0? Is it a good enough power plant to tow 6500lbs and haul another 2000 on top of that? Obviously I know it’s not a diesel, but does it get the job done well enough for the 25 times a year I tow or haul heavy stuff?
 

NC-smokinlmm

<<<Future tuna killer
May 29, 2011
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Keep your 16, they are worth stupid money and they aren't going to get any cheaper. My buddy just paid 54k for one with 9500 miles on it and flew halfway across the country for it. They will hold value like lbz or better...
 

ShopSpecialties

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Jun 4, 2008
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I know a few people who went from 6.0 to the 6.6 gasser and they like it much better. My neighbor sells/installs DewEze bale beds and he is starting to see more of them and no complaints yet. I have heard of people getting 17 MPG highway driving the speed limit which I think is decent for 401 HP and 464 torque which is much better than the 6.0. I think GM screwed up by not putting the 10 speed behind from the start.

My van is coming up on 500,000 miles and since 2016 was the last year GM put the 6.6 diesel in the vans I am thinking bout going back to gas. I have never been a fan of the 6.0 but this new engine has me interested.
 

KyleC4

Tech
Dec 30, 2016
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The 6.6 is direct injected. I’d take the 6.0 over it due to my reservations about DI. They do drive nice though. The 6L90 feels good behind it. Just wish software was different. Reliability is still in the air. Only customer I know around me only has approx 10k on his.
 

Cougar281

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Sep 11, 2006
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The 6.6 is direct injected. I’d take the 6.0 over it due to my reservations about DI. They do drive nice though. The 6L90 feels good behind it. Just wish software was different. Reliability is still in the air. Only customer I know around me only has approx 10k on his.
What's wrong with GDI? DI in general has been around for at least 20 years, and GDI has been around for at least 10 years... My 2010 CTS has the LLT 3.6L DI and I haven't had a single issue with it. GDI gives the benefit of being able to run more aggressive timing and/or lower octane fuel. The LLT is 11.3:1 CR, which if it wasn't DI, would pretty much require 93, but 87 is safe and recommended in the user manual (I still run 93 though). The ONLY issue with GDI that I'm aware of is coking the valves due to the pcv. Without detergent gasoline being sprayed on the valves, there's nothing to clean them. A good catch can setup can take care of that. Overall, I wouldn't be too worried about GDI.

Sent from my 2PZC5 using Tapatalk
 

LBZ

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Ya my sled and my wife’s car are both DI and never had a hiccup yet.

16’s up here don’t hold there value any better than an lmm. Everyone seems to want an L5P. But if one of y’all cross the border folks want to buy mine, make me an offer!!
 

Dozerboy

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Jun 23, 2009
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Ive heard they tow great and get good mileag. IIRC someone here posted they got one a while ago. I love the 6.0 other then some recent issues they are having. My only concern about 6.6 would be reliability, but I doubt GM would put out something that wouldn’t make it at least 100-150k. If that’s all the longer you think your going to keep it.
 

Chevy1925

don't know sh!t about IFS
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Oct 21, 2009
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i think as long as you are ok with missing the torque the diesel gives, you would be happy. I have a few friends that went from diesel to gas and then back to diesel pretty quick because they missed the torque when towing.

ive wanted to give a HD gasser a shot with a supercharger on it (try to buy and make the dealer install it so it still warrantied). i feel the only crap part would be fuel mileage and possibly a trans issue down the road. The 10 speed behind the 6.6 gas would have been sweet for towing but i have a feeling would be constantly shifting when unloaded
 

fl0w3n

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Jan 8, 2015
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i think as long as you are ok with missing the torque the diesel gives, you would be happy. I have a few friends that went from diesel to gas and then back to diesel pretty quick because they missed the torque when towing.

ive wanted to give a HD gasser a shot with a supercharger on it (try to buy and make the dealer install it so it still warrantied). i feel the only crap part would be fuel mileage and possibly a trans issue down the road. The 10 speed behind the 6.6 gas would have been sweet for towing but i have a feeling would be constantly shifting when unloaded
I’m in that boat. Sold my LBZ, got a 6.0 2500 Suburban with 4.10s and a 4L80. Spent the first year thinking the thing was seriously hurt or burned up because there was no way people use these as a serious work truck. Came up with tons of ideas in my head about small cams/long tubes/tuning/etc, but wound up going back to a Duramax and dang I missed it.

I liked the 6.2 Fords better than the 6.0 Chevy, although part of that may have been comparing 6 speed to 4L80. The 6.0s with 6L80 is probably a more fair comparison
 

LBZ

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I feel the current 10 speed in the dmax might be a bit heavy to spin for the old gaspot. A lighter 8 speed would be more ideal I think. But better built and heavier than the one in the 6.2 gm 1/2 ton.

At work we’ve been forced into the 7.3 Ford since they quit making the v-10. Nothing but engine problems but the trans in it seems to work well. It would be better with a little lower 1st And second gear ratio but it makes the truck move pretty good.

I pick up my camper trailer tomorrow and a demo ltz on Wednesday so gonna pin on to the trailer and load up my atv and see how it feels.
 

fl0w3n

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You’re having 7.3 problems? I’m curious to hear about them.
Also definitely very curious to hear about the 6.6 demo and how the two compare
 

KyleC4

Tech
Dec 30, 2016
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What's wrong with GDI? DI in general has been around for at least 20 years, and GDI has been around for at least 10 years... My 2010 CTS has the LLT 3.6L DI and I haven't had a single issue with it. GDI gives the benefit of being able to run more aggressive timing and/or lower octane fuel. The LLT is 11.3:1 CR, which if it wasn't DI, would pretty much require 93, but 87 is safe and recommended in the user manual (I still run 93 though). The ONLY issue with GDI that I'm aware of is coking the valves due to the pcv. Without detergent gasoline being sprayed on the valves, there's nothing to clean them. A good catch can setup can take care of that. Overall, I wouldn't be too worried about GDI.

Sent from my 2PZC5 using Tapatalk

I’m not going to go into detail about issues or not with injectors in these V8 DI motors. Not trying to slam anything. It’s probably bias of me since I’m in the dealer and see a different volume. Maybe it’s more fuel quality related to anything other than components used. Maybe other states don’t see the same issues.

And to the OP. Also make sure of the warranty. I think they’re lower now at 5yr/60k powertrain.
 

LBZ

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Most gasser’s I’ve seen only come with 5yr/60miles warranty. Been the norm for awhile iirc.

The 7.3’s we have are both under 8000 miles. One is on its second engine. Both have blown multiple tips off of injectors one blew a couple spark plugs out of its heads. Broken valve in one of them also. Now one has a rattle at idle that sounds like a broken flex plate lol. They tried blaming the issues on our marked gas and we were supposed to be running clear in both but one is getting purple daily and the other clear and a little purple here and there and so far 2500miles no issues-a record amount for both without being back in the shop.
 

LBZ

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They still blow plugs out the heads? Haven’t heard that yet from Ford guys around here.
Yup. Two holes twice in the one truck and just one hole once in the other as of last night. Don’t know why. Ford doesn’t tell us much.
 

LBZ

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Pulled the trigger on an AT4. Pick it up Thursday. They gave me a good price for my lml and I guess it’s going to the states.

Stripped everything off my truck yesterday and selling it all as I’m starting over fresh with this truck so have an AD150 with about 6 months on the pump/motor for sale as well as a 60gal aluminum slip tank with small transfer pump and filter, and my sled/atv deck as well.

Gave it one last burnout in the ol girl too after I stripped it.
 
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