Yet another MPG question...

[bigj6360]

Hi all,
I am looking to buy an Avalanche in the next few months. I have been searching info on these things so much that I think my wife has some type of addiction to it. Maybe I do, and Maybe... I do. Anyway, I have particularly been looking at MPGs. I really want a 2500, but I believe a 1500 would be enough truck for me... I'm not sure yet  if I only want to go for enough .

I have seen that people with a 1500 get between 12-24mpg, with a large amount saying they average between 14-17mpg. I have also seen that people with 2500s get between 9-17 with most seeming to average between 11-14.

Here's my question, and it is directed to those who are completely stock, as I will not have the money to by mods for a long time (longer if I get a 2500 ). It is also directed to those who are familiar with 2500 4x4 and 1500 z71 gas mileage (as those are the two types I am looking at). Ok, for real... my question: Are my assumptions on gas mileage correct?

Primarily the truck would be driven unloaded. 2-3 times a month it will see a light load (about 800-1000lbs), about every 6 months it will see a heavier load (~3000lbs) and about once a year it will see about a week long tow of about 5000 lbs.

Sorry for the long post, but I just want to make an educated decision but for real I do :.

Thanks in advance to those who sat and read through this book.
-Me

[jimbo53188]

if you can live with the mileage penalty , go for the 2500. you will never have regrets towing any of the weights you mentioned, you get all 1 ton running gear and still have a smooth ride.if you opt for the 1500 series look for 4:10's so you have max towing capacity. 

[bigj6360]

I've seen wildly differing numbers of the 1500 side of things. Would it be safe to say that on a z71 with 4.10 gears a good average would be 15mpg? I guess it depends on driving style and location, but lets get a little hypothetical  and say that, all things being equal, a truck like this and a 2500 4x4 would only see a 3-4mpg difference? (12 vs 15-16 or 14 vs 17-18 avg).

I guess what I  am looking for is some type of justification other than, "i want it I want it, can I have it, please please please?"

a little more info regarding my driving style: I dont mind driving 65 if i have to just not all the time.
I dont mind driving like a granny if i have to, just not all the time.
So I guess a good estimation would be 50% granny driving 40% Normal and 10$ hot rod would be more my current style of driving.

thanks

[Flint4x4]

Keep in mind some people post DIC mpg rather than actual, it's pretty accurate highway but iffy city or mixed.

There are far more used Z71s out there to choose from, it can handle 5,000# once a year easy enough.

Then again a few people will tow 10,000# + with thier Z71, I'd try to avoid buying one of those    

[bigj6360]

 

Thanks for the help guys

[kiser02av]

Welcome to the club...

I have an 02 1500 z71 with 3.73 gears. Driving mostly unloaded (maybe a suitcase or something going back and forth to college) I get low 15's in the summer going 80-85. In the winter its hard to say an exact number because of more idle time but I get about the same because I drive slower in the winter (70-75). I think you should be able to get away with the 1500 for you needs. I don't see 5,000# once a year to be a problem at all. I have loaded mine down pretty good and haven't had and issues.

[jcooper]

I have a 2004 1500.  12-13MPG around town depending on how it is driven.  18 MPG steady 70-75 Miles per Hour on road.  Have seen 20 MPG one time doing 60-65 MPG on low speed highway.  Count on aroufn 14 to 15 MPG average...

[avyfanohio]

My 02 z71 gets 18 mpg highway running at 65-75 mph. In town it is closer to 14 mpg. I have loaded it or pulled a 5 x 8 trailer loaded with firewood. I have had no problems.

[anglarry04]

I've seen wildly differing numbers of the 1500 side of things. Would it be safe to say that on a z71 with 4.10 gears a good average would be 15mpg? I guess it depends on driving style and location, but lets get a little hypothetical  and say that, all things being equal, a truck like this and a 2500 4x4 would only see a 3-4mpg difference? (12 vs 15-16 or 14 vs 17-18 avg).

I guess what I  am looking for is some type of justification other than, "i want it I want it, can I have it, please please please?"

a little more info regarding my driving style: I dont mind driving 65 if i have to just not all the time.
I dont mind driving like a granny if i have to, just not all the time.
So I guess a good estimation would be 50% granny driving 40% Normal and 10$ hot rod would be more my current style of driving.

thanks

with all you said, a 1500 would be sufficient.   If anything, like already said, make sure you have the 4.10 gear ratio.   I have a z71 with the 3.73 and towed a 3,000 pound pick up behind me for 2,000 plus miles across he south, and had no issues.   I get 15 mpg in town, as high was 21 on the highways, usually around 18.

[lurchsavalanche]

I have a 2004 1500.  12-13MPG around town depending on how it is driven.  18 MPG steady 70-75 Miles per Hour on road.  Have seen 20 MPG one time doing 60-65 MPG on low speed highway.  Count on aroufn 14 to 15 MPG average...

Same mileage on my 04 also, it has 4.10 ratio and 275/55/20 tires. The speedo is reading 65 MPH and my Garmin GPS is showing 70 MPH, so on mine there would be a tiny bit of % to be adjusted for accuracy.

[PerfectReign]

Look at it this way.  How much difference per year is it and how much will it affect your overall life?


Take the annual amount of miles you drive on average. I drive about 21,000.

Take the cost of gas - I fill up at Costco and pay around $2.80/gallon right now.

Now figure your cost per year at 14 MPG (average) for a 2500 and 17 MPG (average) for a 1500. 

For the 2500, you'd estimate:  (21000 / 14 ) * 2.8 = $4,200 per year in gas.

For the 1500, you'd estimate: (21000 / 17 ) * 2.8 = $3,458 per year in gas.


From the estimate, if I were to have a 2500 instead of a 1500, I'd be paying $742/year more in gas. That comes out to $61 a month.  Not a big deal, IMO.  If you want the comfort of towing, the $61 extra a month seems like a good deal.


In hindsight, I kind of wish I had a 2500, simply because of the presumed reliability of the HD transmission over my tranny.  Of course, my truck is a tad over 3 years old and has 65,000 miles, so I guess I'm doing alright.

[bigj6360]

From the estimate, if I were to have a 2500 instead of a 1500, I'd be paying $742/year more in gas. That comes out to $61 a month.  Not a big deal, IMO.  If you want the comfort of towing, the $61 extra a month seems like a good deal.

In hindsight, I kind of wish I had a 2500, simply because of the presumed reliability of the HD transmission over my tranny.  Of course, my truck is a tad over 3 years old and has 65,000 miles, so I guess I'm doing alright.

This is the ($5 word) conundrum (/$5 word) I find myself in. I know several people who have Suburbans and Yukon XLs and three of the six have all had their transmissions replaced, and.. maybe this is coincidence but all three of them have 4 wheel drive, which is what I will most certainly get. And on top of that the average cost for a transmission replacement can be (assumption based on my experience with my '03 Bonnie) upwords of $3000. So say you own a half ton and your transmission goes out, the person sitting next to you in their 2500 will get to drive for about 4 years until the difference in mpg makes up for the cost of a transmission replacement.

I am really trying to get myself to get a 1500 z71. I guess I'm just tired of transmission problems (2 out of last three cars have all had to have them replaced or rebuilt during ownership).

thanks again for the replies.

[ltxi]

4wd has nothing to do with it. The 4L60E in the 5.3 subs/av is marginal for the application. The "good news" is that 1) most don't fail even if abused and 2)if it does fails and you go to a quality rebuilder, like Jasper, you will only have to replace it once.

As to my experience with mileage....nbs 5.3/4:10 gears....overall average 16.5 mpg in daily driving with 75% of that highway....an honest high of 22.5 running east across mostly Wyoming unloaded @ average 75 mph, Salt Lake City to Denver, with a heavy tailwind....an honest measured low of about 14 even running west across Kansas/Colorado, Hays to Denver, into the wind at 80/85 mph average with maybe 500# in the bed.

Better mileage and R&H than I got with my 2000 5.3/3:73 ext cab Silvy over eight years.

[MyBigToy]

This is the ($5 word) conundrum (/$5 word) I find myself in. I know several people who have Suburbans and Yukon XLs and three of the six have all had their transmissions replaced, and.. maybe this is coincidence but all three of them have 4 wheel drive, which is what I will most certainly get. And on top of that the average cost for a transmission replacement can be (assumption based on my experience with my '03 Bonnie) upwords of $3000. So say you own a half ton and your transmission goes out, the person sitting next to you in their 2500 will get to drive for about 4 years until the difference in mpg makes up for the cost of a transmission replacement.

I am really trying to get myself to get a 1500 z71. I guess I'm just tired of transmission problems (2 out of last three cars have all had to have them replaced or rebuilt during ownership).

thanks again for the replies.

You really should be OK with a 1500. The best insurance policy you can get yourself for the tranny is a good aftermarket stacked-plate cooler like a B&M Supercooler or a Tru-Cool unit; I've got the Tru-Cool. Heat is the enemy of a tranny and the cooler should help it live a much longer life. A Corvette servo will also help a little as it gives more apply force on the clutches. You should be able do both of these for less than $150.

I'm in a little different boat than you in that I do tow some but my truck is really my play-toy. With the supercharger and a cam sitting on the shelf ready to go in it's not a question of if but when my tranny will go out even though it's been built some already. When mine goes out I'm going straight to FLT for their Level V (possibly Level VII) built tranny.

I forgot to answer the mileage question - my long term mileage is somewhere between 14-16 mpg; that's with 4.10 gears. None of the mods I've done have made an iota of difference and they've mostly been added one at a time. The exception is the supercharger - when my foot's in it the mileage goes down considerably. 

[PerfectReign]

The 1500, when fitted with the 4L60E tranny should be okay for most applications. The 4L60 - a non electronic version which served me perfectly well in my 190HP '95 Jimmy - is designed as a light duty transmission with an upwards HP limit of 350 HP. The stock Avalanche has around 315 HP so there should be no problem, though the limit is close. 

If you do any mods to increase torque or HP, you might run into trouble. You can then easily opt for a Jasper rebuilt (as mentioned above) or get a 4L65E or even the newer 4L70E.

My suggestion as cheap insurance would be to annually clean out the tranny fluid and get a transmission cooler, even if you don't tow. (I put in a transmission cooler last year.)

[maxpower220]

I owned an 02 Z71 (4x4) with 5.3 and 3.73. I checked mileage every tank for 5 yrs. 13.5-13.7 around town and 17.3-17.6 Hwy (76mph). 
I drive like a grandpa, so I can only assume that mileage could get worse and not better in the truck that I owned.
5000lbs of boat and stuff from Fl to Ca to Fl, I got 12mpg average at 70mph.

I am getting 16.9 city with 09 5.3 with 3.42 (2500 miles total).

[kiser02av]

I did an experiment yesterday during a long drive. At 55 mph with no wind and mostly flat ground (some small hills). I went 111.6 miles off of 4.254 gallons of gas. That is 26.23 MPG!!! I had a light load in the box (suitcase, smalll toolbox, winter survival kit, and a few other small things). This is by far the best I have ever done, by about 7.5 MPG.  The next leg of the trip I bumped it up to 60 MPH. I dropped to about 20 MPG. Then I bumped it up to 75 MPH and got about 15.5. Its amazing what slowing down a little does for mileage.