New here and have a few questions about the 8.1. I have been driving a 96 K2500 with a 6.5 diesel since 2001, using it to pull a 30 foot trailer weighing in at 6500 lbs. I have done some mods to the truck and liked the way it pulled and handled with the trailer.

My problem is I bought a 33ft 12,000 lb fifth wheel with a 2200 lb pin weight. I feel that it's just too much for the 6.5 diesel with a 120,000 miles, plus the pin weight will be a little heavy.

I am now looking at a 2005 K3500 with a 8.1. I wanted a newer diesel but can't justify paying the premium for a Duramax. I only put about 5000 miles a year on the truck, towing maybe 25 percent of the time.

Is there anyone here that has owned a diesel and switched back to a gasser?
How about having regrets to switching back?

With gas being .35 cents a gallon cheaper in PA, it helps with my decision on a cost basis. I figure with what I save buying the 8.1 and cheaper fuel, the fact that I don't drive a lot of miles, that this is the way I should go.

Sorry for the long winded question, looking for opinions from people with experience with both engines.

Thanks, Don

imo, if your not going to be driving the truck that often, you'd be happier with the diesel for the extra pulling power, and fuel mileage while towing will be better than with the 8.1 gasser. i have a buddy that had a gasser to pull his 5er until he bought a 04 durxmax, he says he will never go back as long as he goes camping.

Fuel mileage is the one thing holding me up on buying the 8.1, though I can save alot on the purchase of a truck with 50K on it. For me, the downside of the diesel is the repair costs and finding a truck with less than 50K on it. Seems like most people that buy the diesels really run them.

I have an 8.1 and pull a 5ver that weighs in at 10K. I have friends that have diesel's and they can't pull any better than mine. Mine is a stock 2x4 extended cab 4:10 rear end 2003 with 53K on it. . Its very hard to justify spending the extra $$$$ for a diesel when they get 2-3 MPG better with approx the same weight. The other adv, is you will not have a $100 oil change. I have read on this forum ,if taken care of, the 8.1 is good for almost 300K miles. I just wish GM had a true good replacment for the big block. My two cents anyway good luck.

Hi Don.
I live in Pittsburgh and just sold my 8.1.
I bought it new in '02 and had 100K on it. I always get a new truck at that mileage.
If I could have bought another new 8.1 in a one ton dually I would have done it in a heartbeat.
I haul a 6 horse trailer that weighs a little over 12K and it handled it with no problems at all.
The only bad thing about the engine is they do burn a little bit of oil. Mine burned a quart every 2,500 miles.
I had a 6 speed manual with 4.10's.
I got 14mpg empty on the highway and 8-9mpg loaded.
Even though I just bought a new diesel (dare I say it, a Cummins) those big blocks are better suited for many people.
- Dave

Thanks for the replies, I think I can live with the lower fuel mileage, with the truck costing about 5 to 10k less than a comparable diesel truck. I won't be putting a lot of miles on the truck, so I will never make up the difference with the better diesel fuel mileage. I change my oil at 3000, don't mind adding a quart in between.

Now to find a clean truck! I looked at one, but have some doubts because of a carfax report. Truck took a hit to the left side front, repairs lok good except for a bumper that is a little offset. The steering pulled a little to the left, dealer says he will get a front end alignment.

Thanks for the replies, I think I can live with the lower fuel mileage, with the truck costing about 5 to 10k less than a comparable diesel truck. I won't be putting a lot of miles on the truck, so I will never make up the difference with the better diesel fuel mileage. I change my oil at 3000, don't mind adding a quart in between.

Now to find a clean truck! I looked at one, but have some doubts because of a carfax report. Truck took a hit to the left side front, repairs lok good except for a bumper that is a little offset. The steering pulled a little to the left, dealer says he will get a front end alignment.

It's a shame you weren't a month sooner. I'm anal about my trucks. Just for kicks, check out how clean this one was!

http://www.daveloreski.com/westernhauler.htm

In your situation, I would get the 8.1. They are great engines and have a ton of power. I have a 2007 duramax and pull a 33' 5th wheel toyhauler, and on the flat ground I only get about 8.5-9mpg. My brother just found a really clean original owner '04, same truck as mine. CCSB with only about 50k on it, and the 5 speed allison. He pulls a trailer nearly identical to mine in size and weight. He gets worse mileage(about 4-5mpg pulling), and probably a little less on the BIG hills. The truck has plenty of power and pulls his trailer almost as fast up hills as my duramax. He pays less for fuel, but uses more of it so that's a wash. He loves that truck. It does burn some oil, but a quart every 3k is nothing. A set of injectors on a diesel can easily run you 3-5 grand, depending where you go. I chose the diesel for longevity, and plan on keeping mine for a long, long time. If you don't put that many miles on a truck then I would choose the gas engine.

8.1 was down rated a bit in HP and Tq in 03+ but it'll still pull just fine. Diesel is great but only if used everyday IMO.

Only 5K miles/year??? Get the gasser

Then get EFI live, kill the torque management and burst knock and see how much it wakes up

i got a really really nice one for sale.......

http://www.pirate4x4.com/forum/showthread.php?t=904433

I went through the same thing as you did when I bought my 2001 HD2500 now. I only put around 4000 miles a year on my truck. The Duramax at the time was around $4500 more than the 8.1L. That was like 4-5 years of driving before I broke even. With the Duramax being new and untested, I went with the 8.1L and Allison.

When I did alot of drag racing, I pulled a 36' 5th wheel with my 1970 GTO (3200 lbs), all my tools, luggage, jacks, spares, etc and the truck never blinked. I got a ticket one time going up the hills on the Mass Pike coming back from Ohio and the Trooper told me I was doing 75 at the bottom of the hill and 80+ when I passed him mid-way. ;)

i LOVE my 8.1. . never have i had any issues with power. . average loaded weight is well over 20k. just get the gasser and laugh at every duramax thats gotta pay so much for oil changes and fuel filter changes and injector changes as regular maintenance. . $5k for the duramax option is ALOT of gas. even premium is cheaper that diesel currently.

Ive had both, you see what i have now. Both the 8100's i had were turds. I had one with a ZF in 02 and one with a allison in 04. The allison truck was alot better than the stick truck but was still a turd. My Dmax will get better mileage loaded than those trucks would combined. By loaded i'm talking almost 20k of gooseneck with antique deeres. 8100 trucks got 5 to 6 mpg. The Dmax will get 12 to 13 with the exact same load.

Ive had both, you see what i have now. Both the 8100's i had were turds. I had one with a ZF in 02 and one with a allison in 04. The allison truck was alot better than the stick truck but was still a turd. My Dmax will get better mileage loaded than those trucks would combined. By loaded i'm talking almost 20k of gooseneck with antique deeres. 8100 trucks got 5 to 6 mpg. The Dmax will get 12 to 13 with the exact same load.


im gonna have to call b*llsh*t on this one. . take that aftermarket programming and exhaust off the duramax and watch the mileage drop to the same point of the 8.1. now of course you will argue that "oh thats what i gotta do to get the mileage" well compare stock to stock and i guarantee you wont be getting double the mileage of the 8.1. in a fair comparo. my 06 big block pulling a 30ft travel trailer loaded, also with 2 atvs on my bed driving like a total ass staying in the hammer lane al the time i got 7.9 mpg. a good friend of mine with a stock 06 lbz hauling a 30ft 5thwheel got 9.9 mpg on his entire trip- not driving like i do. not worth the investment. . in order to ofset the cost of just the dmax engine price you would need to drive well over 200k miles and get at least 18mpg average across the board. and remember that unless you are very handy and know some people that have connections good luck working on that duramax. im a master certified chevy tech and i still cringe anytime i get one in my stall. sorry guys i do love my gm products but just cant see spending all that extra on maintenance and fuel on top of the original purchase price. . however at the end of the day its your decision. there i said my piece

Call B.S. if you want but i bet it would still get double the mileage even with a stock tune. A friend of mine had a brand new 01 8100 with allison and he hated the truck from the get go. He had the same complaints about it that i did about mine. No power and downshifting all the time even with a empty 16 foot car trailer. He had previously owned a 98 1 ton crew cab with a Vortec 454 and 4.10 gears. The truck also had a 6 inch lift and 35 inch tires. The 98 would pull 10 times better than the 496 ever would. His 01 was a regular cab lighter wieght truck with 4.10 gears. That 98 crew would tear thet 01 up with a trailer on.

Thanks again for all the replies, I think I will be able to live with either truck, I just figure I can save some money by buying the 8.1.

Having owned a 6.5 Diesel for 10 years now, I am familiar with the different characteristics between gas and diesel trucks. My truck now runs at 1900 rpm's@65 mph, and pulls decent on mild grades with 6000lbs behind it. This engine also makes its peak torque about 1800 rpm's, but definitely pulled better after putting on the 4 inch exhaust. I feel that that the new trailer will be too much for this truck. The 8.1 makes its peak torque at higher rpm's, so I will expect more downshifting on hills.

I worked for a major oil company, and know it don't cost much more to blend 15/40 motor oil. I also got whacked with 70.00 dollar oil change, that was the last one, do the rest myself.

ha ha ha . . . my how funny you think you are. i will fill you in a little. between myself and my brother we are on our 5th big block trucks. my 99 one ton srw was a great truck but not even close to my 06. . as for downshifting..... hmmm lets think about gas engines and the way they are designed. not for lugging around at 1500 rpms. yes they will do it but after they downshift they upshift again and pull the remainder of the hill. and the majority of shifting has abosultely nothing to do with the ecm. . its the intent of the allison to shift when it feels needed. bottom line big block still cheaper from purchase to sale date. and will get the job done just as easily

Nothing funny about it!! I told you about experiences on 3 different trucks owned by 2 different people. If you guys don't wanna hear about real world experiences wich is what the original poster wanted so be be it. There is no fricking reason a almost 500 ci. engine in a 3/4 ton truck should be downshifting on hills with a empty car trailer that may at the most weigh 2500 lbs. PERIOD...You guys can have all that you want but its not for me. My truck in sig will pull anything all day long at 70 plus in overdrive wich is something no factory installed big bock will ever do.

X2 Blk04HD. My BBC would never out pull, get better mileage, or outlast my Duramax. Anyways!

Having owned a 6.5 Diesel for 10 years now, I am familiar with the different characteristics between gas and diesel trucks. My truck now runs at 1900 rpm's@65 mph

If only you had the 4.11's in the 6.5 truck I'd say you'd be happy with it in a 12K fiver. I pull one about the same weight with a 6.5 and it does fine, and there's another member (whom I can't think of off the top of my head now) pulling a 16K fiver as well.

However, based on your RPM's quoted above I'm guessing you have the 3.73's which unfortunately reduces your towing abilities fairly dramatically with the 6.5...

If only you had the 4.11's in the 6.5 truck I'd say you'd be happy with it in a 12K fiver. I pull one about the same weight with a 6.5 and it does fine, and there's another member (whom I can't think of off the top of my head now) pulling a 16K fiver as well.

However, based on your RPM's quoted above I'm guessing you have the 3.73's which unfortunately reduces your towing abilities fairly dramatically with the 6.5...

Yea, it does all right with 6500 to 7500 lbs, but I think i'd kill it with the new fiver.

Has anyone heard if GM is bringing back this big block or some type of equal replacement for it?

If only you had the 4.11's in the 6.5 truck I'd say you'd be happy with it in a 12K fiver. I pull one about the same weight with a 6.5 and it does fine, and there's another member (whom I can't think of off the top of my head now) pulling a 16K fiver as well.

However, based on your RPM's quoted above I'm guessing you have the 3.73's which unfortunately reduces your towing abilities fairly dramatically with the 6.5...

Just ran the vin# on my truck, yes it does have the 3.73 rear axle.

Thanks to all for the replies, picked up the new ride today. 05 Silverado LS CC 8.1 4X4 DRW with 22000 miles on it. After 300 mile ride home, used 3/4 tank of fuel, will top off and check mileage tomorrow.

Congratulations! Now get the plug gap closed up,a good tune,180 tstat,and enjoy the truck.

I had a 2002 8.1L with 3.73 gears towing a 34ft 10,500lb 5th wheel. It would do the job but would downshift out of OD on any little incline. Get one with 4.10 gears and it will be better suited for that size load. The 8.1 would also get around 7 mpg while the dmax gets 11-12 mpg same 5ver, same travel speed and terain. The dmax also shines while not towing getting 18-21mpg on the highway.

If you only put 5,000 miles a year on it and can find an 8.1l with 4.10s I would say it would do the job.

i pull a 40' enclosed that weighs right around 19-20k with my 8.1 with 4.10 gears but i have a zf im sure it makes a lil difference once i get rollin i VERY rarely hafta shift out of 6th gear unlus its a mile long hill or better get between 8 and 9 towing 7 in the wind that 8.1 will pull ANYTHING on wheels their were 350s pulling what u pull long before the dmax was even thought of. im not trying to be a gas 8.1 positive speaker but to think you need a diesel to pull is crazy that being said i have a dmax to lol