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Gas milage.


New Member
Jul 13, 2007
I just bought a 02 2500 av. Took a trip out of town towing my 30 ft 6900 hundred poud travel trailer. Got about 5.5 mph. Did like this very well. How do I get bettewr mph.
Tow less weight.  Keep foot out of it.
That seems low, even for that monster engine. I keep hearing around 10mpg, towing or not...........
The rear end is 3.73. With tow haul being used. Foot not in it. Going about 70 and trying to keep it at 2400 rpm.
I have nothing constructive to add but,


To the club!​

Why don't you update your location information or at least tell us where you're towing.  Was it all uphill?  Headwind?  etc.?  One thing's for sure.  You're not helping your cause by trying to keep it at 70MPH to achieve better MPG.  Take it easy and enjoy the ride.  You'll get to your destination in due time.
I live in  Cottage Grove MN. Was going N to to Alex. on 94. Wind not bad. Had it in D and using cruise. Maybe not the best idea.
I towed 10,000 lbs and was between 8-9 mpg at about 60 mph. I have a 4.10 and used 3rd gear most of the time. If you push 70 mph you are best off in OD with the 3.73. Try backing down to 60 or 65 and see what happens. The travel trailer has a LOT of drag which goes up by the square with Velocity increase.

mine is around 10 mpg everyday driving with 4:10's & 33's.

best I saw was 13 mpg on a 200 mile trip, cruise set at 70 mph.
I get 7-10 towing 9000-13 000 lb.  However that is all 4x4s.  An rv will act as a giant sale, as speed increase it, really will hurt mileage.

My worst tank was 5.5 mpg on cruise at 80 mpg on I25 from Buffalo to Douglas.  30-40 mph side/ headwind, lots of rolling hill, 102 deg F, ac on towing 11 000 lb on my big trailer (34' flat bed). 

I have seen as little as 2.5 on the DIC running wide open up some of the mtn passes though, so I am sure you can use the fuel if you want. :D

Take it off cruise, speed up a little at the bottom of a hill, back out of it if you can as you near the top.  It will really help.  Cruise doesn't react to the hills, it just dumps more fuel in as speed is reduced.

Now if you get into big passes, it doesn't matter much.  Put the hammer down, and fill up for gas as needed.  :B:
I'm kind of shocked here about people using an Avalanche as a tow vehicle and then complaining about the gas mileage.

I use mine to haul a 7,000 lbs racecar trailer and usually have about 500 - 1000 lbs of tools and supplies in the bed.

I live in Pennsylvania, where there are hills and mountains and all kinds of things that would make it almost impossible to go 70 mph, towing my trailer.
Usually the trailer will sway all over the road when I get it over 55 mph, but even if it didn't.  I still wouldn't want to tow anything for any amount of distance at that speed.

My '02 gets around 12 mpg around town and maybe 16 on a trip, if I keep it under 60 mph.  Every mile per an hour over 55 costs me 1/2 a mile per a gallon over that.

Towing the trailer, depending on where I am at, I usually get 4 to 8 mpg @ 55 mph. 

All I will say is that an Avalanche is a poor excuse for a tow vehicle, it probably had as much as anything else to do with the fact that the transmission went out at 70,000 miles.

The tow haul mode locks the torque converter up and keeps the transmission in the lowest possible gear as long as possible, so as to protect the transmission.  It will probably keep the transmission cooler - due to the fact that when the transmission is in a lower gear, the transmission pumps more fluid than it does when it lugs.

You might save a gallon or two of gasoline by not turning the tow haul mode on, but the money that you spend on transmissions will be several times what you save in the long run.

All 3 of the transmissions that I had put into the Avalanche broke the Shell in the transmission.  Even an updated version - Stainless Steel shell broke, along with a heavier version sprag and planetary gears.  The 4L60E was not a very good transmission..
Yeah you're right, I can't believe people use these things as a tow rig....


I mean I only have 60 k miles on mine, about 15k miles towing.  Picture is 13 000 lb by the way, 20k lb gross.  I have ran that 80 mph no problem, and over huge passes (Vail, 11 000') not at 80 mph though, drop to about 40 for about 3-4 miles, adds about 5-10 minutes to the 6 hr trip.

The 4L85E is doing just fine, thanks for asking.   :B:

Wait you said 4L60E...  Perhpas you have a 1500?

Drivetrain is totally different except the Nvg246 Autotrac t-case.  (which is rated for 5555 ft-lb of torque).  Rear suspension is totally different as well.  I have never had any sway, but could be a function of the rear leaf springs the 2500 have? :B: :B: :B:

I never complain about mileage.  Especially at $1.35/gallon
I just towed Pittsburgh to Marco Island, FL and back with a car trailer and SUV, total weight 6400k. Got an average of 10.8 MPG! Cruising at 75mph.
avalonandl said:
Darn good at that speed.


x2!!  Of course, my buggy is FAR less of an aero-friendly load..  Got 8.5 going 75-80 and 10.0 going 65 with it, and several hundred pounds of cargo in the bed...