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Discussion Starter · #1 ·
First I'd like to apologize if any of my questions below are tired and beaten to death already. I performed a search and wasn't happy with what I was finding. Second, I'd like to thank everyone in advance for your help.

I'm in the process of truck shopping. Initially I was looking at just basic 2500HD 6.0L trucks, but I realized that my use would be too much for the truck. I was also given the advice that whatever I do I get an Allison transmission. This puts me in my current situation. Do I get the 6.6L Duramax or do I get the 8.1L Vortec?

I'm buying a Crew Cab Short Bed regardless of which engine I go with. Most likely I will be getting a 4x4, but I am buying used so I would jump on a good deal regardless of 4 or 2 wheel drive. I will be driving the truck everday to work, which is about 16 miles each way, 4 miles on 'city' streets and the rest on I-95. I live in New Jersey so we have warm summers and cold winters.

In addition to the daily commute, I'll be towing a camper with it. Currently I have a 30' 7500# travel trailer, however in the next 18 months or so we will be upgrading to a 5th wheel - the ones we are currently looking at are in the 12500# - 14000# range (gross). I have been told that the 8.1L is the way to go, but all the people we camp with are gas people and I hear nothing but negative about diesel, which is why I cam here - I'm hoping to hear from your side of the fence.

As I said, I am getting an Allison transmission regardless or gas / deisel. So I'm looking for any comparison information you may have to offer between the 6.6 and the 8.1. I've heard nightmares are maintenance on diesel trucks. I have absolutely no knowledge or experience of diesels at all so I don't know what to believe.

Are there any reliability issues with the diesel Vs. Gas. I know the 8.1 burns oil, do diesels burn a lot of oil? I know I will need more oil when performing changes, but does it also burn a lot between like the gasser? Also are the maintenance intervals the same, and am I really going to need 12qts of oil to perform an oil change?

I probably drive 10,000 miles per year, depending on where we go any where from 3500 - 6500 of that can be towing. I just don't want to buy a truck, and then find myself wishing I bought something different once I start with the 5th wheel - or after owning the truck for 4,5,or more years. How many miles can I expect to get out of a well maintained D/A setup? My best guess for an 8.1, based on my past 5.7 experience, is about 230k or so - will I get substantially more life from a well maintained Duramax?

I do apologize if any of these are dumb, or repeat questions. I also really appreciate any input you can offer. I always deal with the same dealer here, and he said he would be more then willing to find me anything I want - but I have to figure out gas or diesel so I can get him searching.
 

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Welcome to the site! Well, the questions that you raise are valid. I have very little knowledge of the 8.1 gasser, but I have driven my 04 duramax for about 2 1/2 years now. When talking about gas/diesel comparisons, there really isn't any comparison between the 2. One thing to look at is the price of gasoline vs. diesel in your area. I know here in Alaska diesel is .40 more a gallon. Overall with mixed driving, you should get better mileage out of the duramax. The mileage will drop to about 10-14 mpg towing, but in mixed unloaded driving you should see anywhere from 16-20 mpg. Maintenance isn't that much more on a diesel vs. gasser. Diesels are real sensitive when it comes to fuel and fuel filters. I always carry an extra filter in my truck and the tools to change it. It takes 10 qts to change the oil, but you only have to change it every 7500 miles or more if you do an oil analysis. In 7500 miles, I typically have to add about a qt of oil. As far as towing power, if you tow with a duramax, I highly doubt you will go back to a gasser. Diesels make their torque at a lot lower RPM than the gassers do. I suspect that the duramax would shift a lot less than a gasser would pulling the same weight. The only nightmares with the earlier duramax's was injectors (01-04 LB7 engines). they are a pain to change when it comes time. The 01-03s are covered by a 7yr/200,000 mile no deductible on the injectors. I am assuming that the 04s will be following soon behind. Some of the 05 LLY engines would overheat. If I were you, I would look at getting an 03 or 04 LB7. You should be able to pick one up at a fairly decent price. Also, reguardless on if you go with a gas or diesel, make sure to change the spin-on filter on the allison about every 5000-10000 miles. It is cheap insurance and it keeps crud out of the tranny. I hope this helps a little on the decision on the 2. I know there will be more people to chime in as time goes on.
 

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I would say diesel if you are going to do any serious towing and plan on having the truck several years. The D Max/Allison combo is unbelievable when towing and GM has the most comfortable cab on the road. Diesel engines really only need two things. Clean air and fuel. I know several drivers that tow for a living that have 250K plus on their D Max. Aside from the problems mentioned above they love 'em. On the 06 the injectors are more accessable so maintenance cost should be greatly reduced over previous models. My 06 has 66K on it without problems.
I would suggest that you consider a long wheelbase if you are going to pull a fifth wheel. The ride is better loaded and empty and you don't have to worry about the nose of that trailer coming through your back glass while backing and turning. Happened to a friend of mine,twice.
IMHO, if your going to tow, diesel is the best choice.
 

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I say Diesel, With the amount of towing you say you plan on doing, the gas milage of the 8.1 will hurt! THe 8.1 will run very close to the same as a stock d-max so really the only diff will be milage. THe maintence will be a little higher on the dmax as it hold 10qt of oil compared to the 7Qt of the 8.1. THe fuel filter is about three times the cost and need replaced every 10k minimum, and the trans filter needs changed often about 7 to 10k miles but this is allison related not diesel!!

Welcome to the site!
Caleb
 

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Discussion Starter · #5 ·
Thank you for the feedback so far. How can I find out for sure which ones have the 200k mile warranty, and does this just cover the engine or the whole drivetrain?

Also since I saw 'stock' mentioned. Would it be worth it to get a Bully Dog, or similar programmer? How do these 'reprograms' effect the reliability durability?

Also I saw injectors mentioned a few times, do these need to be cleaned regularly or was there just a problem with some of the injectors used during certain periods of build time?

As for the long bed, parking is a nightmare where I work and the long bed crew is just too much truck to take in and park everyday - I've struggled with this decision for a while.

In regard to fuel, I live in south jersey and diesel is about 2.25 right now, which is what super gasoline is running.

Going back to engines, I didn't realize there were different versions of the 6.6 Duramax, is the LB7 the most reliable?

Thanks again for all the info. I'm leaning towards the diesel, but not knowing anything about them I want to make sure I'm well aware of what I'm in for, and what I'll need to do to keep it running.

Charlie
 

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Thank you for the feedback so far. How can I find out for sure which ones have the 200k mile warranty, and does this just cover the engine or the whole drivetrain?

Also since I saw 'stock' mentioned. Would it be worth it to get a Bully Dog, or similar programmer? How do these 'reprograms' effect the reliability durability?

Also I saw injectors mentioned a few times, do these need to be cleaned regularly or was there just a problem with some of the injectors used during certain periods of build time?

As for the long bed, parking is a nightmare where I work and the long bed crew is just too much truck to take in and park everyday - I've struggled with this decision for a while.

In regard to fuel, I live in south jersey and diesel is about 2.25 right now, which is what super gasoline is running.

Going back to engines, I didn't realize there were different versions of the 6.6 Duramax, is the LB7 the most reliable?

Thanks again for all the info. I'm leaning towards the diesel, but not knowing anything about them I want to make sure I'm well aware of what I'm in for, and what I'll need to do to keep it running.

Charlie
One of the mechanics I work with has an '02 2500HD with an 8.1, it is a sweetheart of an engine, it pulls good, revs good and gets fair mileage, that said, I have to tell you that as much as I love big blocks, (454, 8.1, 460, cadillac 472 or 500 or the dodge v-10, not the ford spark plug spitting out v-10 though), I will never go back to gas for my main puller, (unless they start turbocharging big blocks and find a way to keep the detonation down!!!) you just can't beat the new diesels, they have incredible torque plus they pull like mad clear up to their redline, which at about 3000 is not as cool as a well built big block that goes to 6500, but they do it easier than a big block, with a much better life expectancy thanks to their lower redline and better design,
we have raced our trucks and he couldn't beat my LLY, so he will get his [email protected]@ kicked by my LBZ once I get it broken in!!
so if you decide to go diesel remember that the '07 classic LBZ D-max and I think the '06 LBZ TOO, have a 100,000 mile powertrain warranty now, that means the whole powertrain not just the engine, which was a big part of my decision to trade in the '05 for the '07, of course the better power and mileage made the deal for me!!
 

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01-early 04= LB7 , 300HP, 520 FT. LB. torque. 01&02 model years had injector problems, but have a 200,000mile warrenty on them. The 03's have the warrenty now as well too! The 04's have redesigned injector and have very few problems, but there have been some.
04 1/2 LLY 310HP, 590 torque, some overheating problems
05 LLY, 310HP,605 torque(i think)
06 LBZ, 360HP,650 torque
 

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Also
04.5-05-06 LLY with manual trans-300hp and 520lbft
06lly with ally 310hp610lbft!
 

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anyone here is going to tell you to go diesel! thats just who we are! we all have one and love our trucks! As much as it sounds you are going to pull, the diesel is the way to go! i run my truck HARD and get 15.1 consistently on average. thats with big tires and a few bolt-ons. There is just something different about having a Duramax. its like a harley, sure there are plenty of bikes, but why not get the best! we are just a different group and spark plugs are for people that cant afford injectors!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
 

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Go with the diesel, its will out power that 8.1 any day, will save you in fuel costs both pulling and not (power for power) and is very simple and inexpensive to upgrade and gain more power than a gasser. Also the diesel will last you far longer. I won't ever buy a gasser again as a tow rig.
 

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Discussion Starter · #13 ·
The problems with the injectors and over-heating, are these things being fixed under warranty coverage? Also are these showing up early in the engine's life span or do I risk running out of warranty?

I'm definitely leaning toward the diesel, and I figured I'd get pro-diesel advice here. I am getting the information I was looking for though such as the good and bad engines, and what to look for when shopping these trucks.

I really doubt I'll be able to pull off buying a new truck, unless I get a great deal on a left over 2006 - so I guess now I'm trying to figure out if I'm better off with an older duramax, or if any year (or build I guess) is ok. Is there any one engine code that is a sure bet to stay away from? And is there any one engine code that is the favored by majority? I'm still trying to get them straight, but I mean should I avoid an LLY and get and LB7 ? I know those might be the wrong codes, but thats kind of what I'm worried about at this point - buying a bad setup when a simple VIN# check could yield a much better vehicle.

Thanks again for your input and taking the time to read this. One other quick question, and please keep in mind I'm completely new to diesels - will I need to keep the engine block heater plugged in to start the truck each morning in the winter? Or will the truck start ok in the cold morning? I live in NJ so I know my cold might not be as cold as other people have it, but I'm just curious at what point I'll need that plugged in .....
 
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