8.1 Haulers only, please! - Montana Owners Club

Art · 02-16-2007, 09:48 AM

Fellow 8.1 haulers... I know that there have been hundreds of articles on "miles per gallon" solo and pulling. I know that diesels are better in this category than gassers. THEREFORE... I was just reading the new Trailer Life and their testing of the 2007 GMC/Chevy. They stated that they got "8mpg in overdrive at 65 mph" and "10mpg without overdrive at 60mph." Now for my question...my signature shows that I tow a heavy fiver (about 15,000 lbs.) I usually get 8mpg pulling at 60-65 mph IN OVERDRIVE! I tried pulling WITHOUT overdrive for one haul and GOT 6.5 MPG! My 4.10 rear makes the truck turn about 2000rpm at 60 with OD and 2500+ without OD. HAVE ANY OF YOU GOTTEN BETTER GAS MILEAGE TRAVELING 60-65 MPH WITHOUT OVERDRIVE? I would appreciate your honesty!

kdeiss · 02-16-2007, 12:14 PM

Art
They were testing a 1500 crew cab with 6.0 not 8.1

Art · 02-16-2007, 02:36 PM

I realize that and considering my bigger, heavier rig the same mileage didn't sound that bad. But I still wondered if other drivers were getting worst mileage out-of-overdrive.

Quote:

quote:Originally posted by kdeiss

Art
They were testing a 1500 crew cab with 6.0 not 8.1

mailmanguy · 02-16-2007, 04:06 PM

Hi Art,

My last fifth wheel weighed in at 12,000 lbs and we pulled it all over the eastern coast. I averaged between 8 & 10 mpg highway. However, going through the state of West Virginia (I-77) I would drop down to 6 mpg. I would not agree with that article's conclusion. I love my 8.1/Allison combo very much and look forward to pulling our new 3400rl this year with it. I realize that this is a little bit heavier trailer, but so far it seems to handle quite nice if not better then my last Montana.

I definitely get better gas mileage in overdrive, than without it. As long as I'm not in a "hard pull" due to a grade incline or strong head wind, I always use the overdrive. Like you, I turn about 2200 rpms at 65mph with the 4:10's and it's comfortable. I've never been one to "crowd" my engine. I'm not a racer. Life is going by fast enough, so I'm going to enjoy the ride.

AZCampinfool · 02-16-2007, 05:04 PM

Art, I average betweem 7.5 and 8.5 pulling the Mountaineer in our sig with 4:10's using the overdrive and tow/haul mode. The gas mileage drops quite a bit if I don't use the overdrive. In fact, the allison tranny does such a good job, I not sure why anyone would do that. Almost every trip we take, we head for the mountains in northern AZ and some of the grades are as steep as any I have seen. I usually don't even touch the shifter and just let the allison and 8.1 do their thing. Works so good that I don't see any need to mess with it.

gbsb · 02-16-2007, 10:48 PM

I have a 01 dually GMC crew cab with the 8.1 allison combo and tow a 3670 RL. On a trip to Iowa last fall we averaged 7 mpg. on the whole trip towing. We try to stay off Interstate Hwy. if possile so had a lot of stop and go traffic. Run in OD and tow/haul at all times when towing. Never tried it without OD.

Art · 02-17-2007, 05:06 AM

Thanks guys for your information and honesty! I guess what I am doing is correct and it's nice to hear it from other experienced drivers. Thanks again!

dscott · 02-17-2007, 09:43 AM

Hi,
I have a 2004 GMC 2500HD SB with 8.1 Allison and 373 gears will I be able to pull my new 3400RL, will be built next week? It's ordered with slide awnings and washer and dryer combo deaier installed.I have never towed any thing with this truck. It seems every body tows with 4.10 gears and over drive. Thanks Don

campbud · 02-17-2007, 01:07 PM

Quote:

quote:Originally posted by Art

Fellow 8.1 haulers... I know that there have been hundreds of articles on "miles per gallon" solo and pulling. I know that diesels are better in this category than gassers. THEREFORE... I was just reading the new Trailer Life and their testing of the 2007 GMC/Chevy. They stated that they got "8mpg in overdrive at 65 mph" and "10mpg without overdrive at 60mph." Now for my question...my signature shows that I tow a heavy fiver (about 15,000 lbs.) I usually get 8mpg pulling at 60-65 mph IN OVERDRIVE! I tried pulling WITHOUT overdrive for one haul and GOT 6.5 MPG! My 4.10 rear makes the truck turn about 2000rpm at 60 with OD and 2500+ without OD. HAVE ANY OF YOU GOTTEN BETTER GAS MILEAGE TRAVELING 60-65 MPH WITHOUT OVERDRIVE? I would appreciate your honesty!

I get 7-8 pulling. Not pulling on the highway 12 (and this is babing it) I have a 2002 2500 4x4 extended cab 8ft bed 8.1 allison 4:10 rear.
Bob

SAndreasen · 02-17-2007, 02:58 PM

I have an 8.1 l with the allison and love it. We get about 8-10 mpg towing and about 14 solo. We just got to Phenoix and are parked next to Snowbird and richfaa. Having a great time and "BOY IS THIS THE WAY TO SPEND WINTER!"

SAndreasen · 02-17-2007, 03:01 PM

PS I have the 3.73 rear end in my 2002 HD extended cab short box pu. Loaded my TT weighes about 11,000

ggranch · 02-19-2007, 03:17 AM

That Trailer Life article has been mentioned in several threads both here and on the RV Net. The TV was new and not broken in, and if you re-read you will realize that the poor little TV was overloaded with just the dry weights. Not a very fair test and a bad example to be setting. They even bragged about how fast it would go (15 over the posted limit). I have not found thier usage articles to be much more than blatant hype for the items they test.

stiles watson · 02-19-2007, 03:48 AM

Sounds like this test was done by the gasoline industry to get you to need more gas.

sreigle · 02-22-2007, 06:59 AM

Dscott, your 8.1 will do fine with the 3400RL. The 8.1 is a strong engine, good towing engine. We have members towing rigs of similar weight with the 8.1. Their only complaint is mpg, but that's a given with a big gasoline engine, including the Ford and Dodge V10's as well as the GM 8.1. We used to have the Ford V10 and towed a Montana of similar weight (3295RK at 14,360 scaled weight). Mileage was about what the 8.1 folks are reporting here.

jpkelpe · 02-24-2007, 03:35 PM

our 2004 2500 had a 3.73 rear end and it pulled our Mountaineer without any problems, even on a steep grade. Milage was about 7-8. we changed vehicles simply because Paul had a "little accident" in it.

Snownyet · 02-25-2007, 02:22 AM

I guess Im wondering why you wouldnt use overdrive? We're not talking 1987 trucks with underbuilt transmissions anymore. The Allison is made for hauling, put it tow haul and go, the tow haul feature will hold out the shifts longer but it'll still use all the gears on the highway.

Montana_1953 · 03-12-2007, 09:07 AM

my 8.1 with 4.10 gets about 10 mpg without the trailer
and 7mpg with

montanaman · 03-24-2007, 06:47 AM

I have a 2002 8.1 Chevy - Gas, and get 8 to 9 mpg when towing, and when in tow, 13 mpg. We have a 14K 5ver and use the tow haul.

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