8.1 Mileage

[FOR MUD]

I drive a high mile ( 215,000 ) 8.1 every day. With me driving like the old man I am......11mpg on a good day. It's not mine, it's a company truck. Last year when they hired a 17 year old for summer help...I would guess 6-8 mpg. I was filling it up twice a day.
None of these miles were towing, just a 03, 2WD, HD2500.
I own an 05, 4WD, HD2500 with 185,000 miles on it that I get 13-14 and 10-11 towing.
To honest, I don't see to must of a difference in the two while towing.
One thing about the 8.1, it likes to run though some oil. Especially when running highway miles.

 

[79rustyk10]

Isn't the oil usage kind of a big block thing?

 

[-stew-]

Isn't the oil usage kind of a big block thing?

Idk. My 454 uses à half a quart every 3-4000 miles.

 

[GWeakland620]

Idk. My 454 uses à half a quart every 3-4000 miles.

My 8.1L does the same thing.

 

[jeff in co]

My 8.1L does the same thing.

Ditto. My 8.1 also about 1 quart per 3000 miles. Just hit 120k.

10-11 around town
12-13 on freeway
8-9 towing....and tows well!

 

[-stew-]

I regularly use three different g30 dually cube vans at work that scale in at 14,000 pounds. 120,000 on one, 104,000 on another, and 170,000 on the third. They seem to average 4-9 mpg. They run all the time. Not unusual to have one running 70-80 hours a week. One of them burns some oil. The other two are better, but still burn a little. But like I said, these never get shut off and its all in town driving.

 

[496truck]

Just realized this thread is a couple months old...

I bought an 04 2500HD 8.1 Allison truck new. Absolutely loved it. It was my DD, grocery getter, scap metal hauler, junk car/off roader/derby car hauler and whatever else I could fit on the trailer or in the back.

Routinely got high 11s to low 12s on a DD basis. My dad's 04 with 6.0/4L80E got (still gets) mid to high 12s on a DD basis. Not a huge improvement in mileage over the 8.1.

Cost to operate/maintain/repair the 6.0 truck will be lower than the 8.1 overall. And if that Allison breaks down on ya, it can get expensive. With that said, if you plan to tow/haul a LOT then find an 8.1 truck. If only towing a couple or few times a year, then a 6.0 would work just fine.