8.1 Vs. Duramax, What To Get?

slow-poke · December 2, 2010

I just sold my 2001 6.0. I want to get a 8.1 or a duramax. I pull a 5000lb trailer through the mountains of Utah. Which would be most economical to drive. The d-max gets better mileage but diesel is more expensive. How long will an 8.1 last. I am looking at an 02 with 133,000 miles, is that to many?

Any input would be greatly apriciated.

Ezrider_92356 · December 2, 2010

its really a loaded question, but day to day cost is lower with a diesel, regular mantinace is more with a diesel. where the gas really has the advantage is when things break. personally i think personalty think the overall gap is pretty dang close with maybe a slight advantage to the d-max unless you end up with any kind of injector issues for the cost of replacing injectors you could replace an entire 8.1L the 8.1l has great power it is a great puller. i sold a power stroke and went to a 8.1L the main thing that swayed me to the 8.1L was that i could get a truck with almost half the millage for the same price. chassis parts don't last any longer on a diesel if anything they fail even sooner due to the extra weight and with the power of the 8.1L being very comparable i felt i was better off with the 8.1L. the 8.1L also has much better throttle response and a lot of tq available right off idle sure make it fun to drive around. and if you live in a cold climate like i do gas motors start way easier

dewfpo · December 2, 2010

You'll get lots of opinions here so take it all in and make up your own mind. What year diesel are you looking at? The newer ones don't do quite as well as the ones just a few years ago so you'd have to take that into account.

5,000 lbs. is not all that much to tow. Heck, a 1/2 ton should handle that fine. Anyway, I live next door in west/central CO and right now RUL is $2.99 and #2 diesel is $3.45 per gallon. You know how many miles you drive and you can do the math.

Have fun reading all the responses.

DEWFPO

THE BIGPUNN · December 2, 2010

Ive had them both and diesel hands down. The 8.1 liter is a great engine. I got awful mileage with it. But you cant compare the raw power of a diesel to a gas. Two different animals. Not to mention the ability to add more cheap power to a diesel with a power programmer. I would still have it if it wasnt for my x!

GMC Denali HD · December 2, 2010

As was said in an earlier post, the 8.1 will do the job but at the expense of MPG. Empty MPG is not bad but towing MPG sucks. As for towing comfort, Duramax all the way. Of course if you are only towing 5000#, a 1500 will do the job just fine with the proper tow package and rear end ratio, but then again you mentioned mountains and you had a 6.0 and maybe that wasn't enough for you. If I had to choose between a 8.1 gas and a 6.6 D/A and I was towing in the mountains, I would pick the D/A. You will get back the extra cost when and if you sell the D/A, no comparison on the resale.

BlackSilver · December 2, 2010

You aren't gonna want to hear this, but your 6.0 would be better for your kind of use. 5,000 isn't much of a load to pull, and for everyday driving 6.0 would be the engine I'd choose.

The 8.1 suffers from gawdawful MPG, and the DMax is meant for heavy work which justifies the price.

I'd go find a nice 6.0.

music · December 3, 2010

Have to agree on the 6.0 for that much weight, or a good 1500/5.3 for best overall economy (depending on how much towing vs unloaded driving). JMHO.

yukon25008.1 · December 3, 2010

If you never had an 8.1 truck youll love it, and they pull great.. i just hauled a 6500 lb camper with near flat tires.. and it was like it wasnt even there..

JoJoJim · December 3, 2010

I have a 2001 8.1 crew cab 4 wd Allison that I purchased new. It has 159,000 miles on it now and engine still performs like it did new. Has always used some oil and that has not changed. Flywheel sensor and front timing chain gasket are the only two failures so far. I am thinking the engine is good for at least 250,000. Gas mileage is an issue as it does suck. 11.5 mpg empty and if pulling maximum trailer weight will run 6 to 7 but I only do that once in awhile. It has awesome power and do have it programmed. If I was pulling a trailer frequently then the diesel is the way to go.

cookeze · December 7, 2010

I have an 8.1 Avalanche and love it. Do the math on how much fuel you can buy with the cost differential between the 8.1 and diesel (purchase cost & maintenance). You'd need to drive the diesel ALOT to come up even. I tow a 9500 travel trailer at 9 mpg and get 13.5 not towing.

chris23120 · December 30, 2010

I have a 2001 8.1 crew cab 4 wd Allison that I purchased new. It has 159,000 miles on it now and engine still performs like it did new. Has always used some oil and that has not changed. Flywheel sensor and front timing chain gasket are the only two failures so far. I am thinking the engine is good for at least 250,000. Gas mileage is an issue as it does suck. 11.5 mpg empty and if pulling maximum trailer weight will run 6 to 7 but I only do that once in awhile. It has awesome power and do have it programmed. If I was pulling a trailer frequently then the diesel is the way to go.

I have a 2005 8.1 that i purchased new. Figured i would get 200,000 out of it. Now with 281,000, i am confident it will get to 400,000. Hasn't had any motor work. New plugs every 100k, still pulls like new, and i don't change the oil till the oil life monitor says 10% (usually 11k miles). My miles are almost all highway, and i get a consistent 13.7mpg with my Crew Cab/8' bed/4wd. I am so happy with this truck that i just purchased a second one since things are starting to get busy at my business and our 4.8 wt can't handle the big stuff. Then new one is a 2001 with 133k and runs like a champ.

When i bought the 8.1, i seriously contemplated a Duramax. Most of my customers run them, or the powerstroke. Most of them though have had some minor (turbo, fuel injector, etc..) problem that has cost 3k or so because of the complex motor. If i were towing a heavy trailer alot a duramax would be my choice but for what we do we run alot of payload but rarely run trailers over 8,000, so i prefer the simplicity of the 8.1 and i like the power delivery much more than the duramax. Plus it basically gets the same milage as my 6.0 did because of the extra gear in the allison and lower (3.73) rear. You can't go wrong with either, you should drive them both.

smoggy · January 2, 2011

I have a 2001 8.1 crew cab 4 wd Allison that I purchased new. It has 159,000 miles on it now and engine still performs like it did new. Has always used some oil and that has not changed. Flywheel sensor and front timing chain gasket are the only two failures so far. I am thinking the engine is good for at least 250,000. Gas mileage is an issue as it does suck. 11.5 mpg empty and if pulling maximum trailer weight will run 6 to 7 but I only do that once in awhile. It has awesome power and do have it programmed. If I was pulling a trailer frequently then the diesel is the way to go.

Which programmer did you go with?

Thanks,

SWDoodle · January 6, 2011

I'd say 6.0 for that weight. The 8.1 is a great engine, but as others have mentioned it will suffer mileage. The 6.0 isn't great either, but the newer ones with the 6-speeds and higher hp ratings are not too bad. Nice thing about the 8.1 though would be the Allison. One other thing to consider is resale value. What I mean is that if you traded it in probably 95% of dealers wouldn't give too much for it because of the stigma of poor mileage undeserved or not. I remember in 2005 when I bought my 6.0 I had been thinking of an 8.1 and the several dealers were like "why would you want that, they get terrible mileage" when realistically they got about 1-2 less than the 6.0. IMO it's one of the things that killed the BB because of the lack of training/positioning of the product.

LCPullman · January 12, 2011

We got an 03 8.1 last year. In our area, the 8.1s are considered more valuable than the 6.0 because their not available any more, and there are some people who simply want them. For us, towing 6000+ lbs around a hilly town the 8.1 is only one mpg worse than our 06 Dmax. The Dmax is more powerful but the 8.1 is great, and it is cheaper to run.

SWDoodle · January 12, 2011

We got an 03 8.1 last year. In our area, the 8.1s are considered more valuable than the 6.0 because their not available any more, and there are some people who simply want them. For us, towing 6000+ lbs around a hilly town the 8.1 is only one mpg worse than our 06 Dmax. The Dmax is more powerful but the 8.1 is great, and it is cheaper to run.

Wow, consider yourself lucky with the 8.1 mileage. Most BB owners I know don't get anywhere close to the duramax mileage towing. I recently traded up to a 08 LMM from the 6.0 gasser and have been keeping pretty close records of fuel mileage. Right now I'm averaging 20-25% better mileage both loaded/unloaded. However, given the cost of diesel here locally @ $0.40/gal more than 87 octane and it is a wash. I pulled a heavy load last Friday (24K GCVW) and the LMM did it with ease. My old 6.0 with that weight would've done it, but struggled mightily and been in 3rd gear downshifting to 2nd on any significant incline. The LMM downshifted once on a steep incline and pulled in 6th the rest of the time on a 85 mile trip bucking a 25 mph headwind. I'm VERY happy with the performance. Do not have any experience with the 8.1 personally, just have had friends with them.