4.10 Rear End MPG

I am considering a '06 Z71 that has a 4.10 rear end.  Anyone have experience on what it will do to the ride and MPG versus the 3.42 read end?

Many threads on this subject...

check sticker for MPG... but I doubt they show different numbers...

as driving style has more impact... on mpg...

4:10 will give better acceleration and towing performance

I have an '05 Z71 with the 4.10. I average 14 - 15 MPG in the city. I don't have many lights on my commute and most of the travel is at 45-50 MPH. I am usually towing when I am on the highway and I get 10-12 MPG depending on the wind. I am towing a 5000# travel trailer though. I would imagine I would be around 18 - 20 MPG on the highway at 60 - 65 MPH, faster than that and it would probably be around 17 MPG.

Hope this helps and by the way ?

irish31790 said:

I am considering a '06 Z71 that has a 4.10 rear end.  Anyone have experience on what it will do to the ride and MPG versus the 3.42 read end?

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Not much diff. in mpg around town. Maybe around 2 less on highway w/4.10's.

The 3.42's will get better mileage, probably 19-20 on the highway. This is at the expense of in-town driveability. There has been a lot of griping about the 3.42 acceleration.

I get 15-16 on the highway with the 4.10's at 75 mph and 14 in town.  If you do any towing, you will be much happier with the 4.10's.

I had 3.73s when I got my AV, for the first 2 years I was getting about 18-21mpg on highway, and 16-17 in city. So I'd assume the 3.42s w/ some mods will get better mpg. After I lifted my AV and went to 4.56s, I got 13-14 h/w, 10-12 city. After the JB tune I got 16 h/w, city?
Hope that helps some.

-James.

I ordered my Avalanche with the 3.73 instead of the 4.11 because I thought it would get better mileage.? Maybe it is because of the mountains and hills in Nevada, you can't drive very far on a level road around here, but the mileage sucks with the 3.73's.? I can get the same mileage driving around in 3rd instead of overdrive because the RPM's rise up into the power range of the engine.?

Don't get me wrong, the 5.3 is a great engine and has plenty of power for normal use, but as with most any engine in most any vehicle by most any manufacturer anymore, the horsepower numbers are good only at the top of the RPM range, and for normal city driving, or even highway driving, we are not even near the real power of the engine.

Case in point, I pulled a 12' enclosed utility trailer back from Michigan a couple years back.? I got about 18 MPG in Michigan, Indiana, Illinois and into Iowa.? When the elevation started to climb it dropped to about 17 mpg, because of the added strain of going uphill and I wasn't in the powerband of the engine.? I was at about 2000 rpm in overdrive but it felt fine and was not struggling.? When I reached Denver the fun started.? As I started to climb the Rocky Mountains I chose to downshift to 2nd gear and it worked great, but the rpm's were about 4000 or so.? I continued using 2nd gear downhill towards Eagle and Vail just to avoid using too much brakes.? I had filled up in Denver and filled up again in Eagle.? To my surprise I averaged 24 mpg on that segment of the trip.? I double checked all the figures and the math and it was still 24 mpg.? Not sure what was going on I ran the same way as I continued west out of Vail and when I filled up again near Grand Junction I was again at 24 mpg.

In my opinion, go with the 4.10 gears.? It will get the engine into the power range and it will be a bit quicker off the light.? You wont be sorry.

Michael

Oh yeah, if I didn't have to change gears in 2 axles I would change to 4.11 or taller, but i don't want to spend that much...yet.

He is wise.  Get the 4.10's.  You won't be sorry 

I have 410's on my 02 with almost 100K on the Ride.
Love them So far no issues.
For the short time the Ride was stock Was Getting 15-16.5 mpg avg mileage.
Now with lots of mods and 35's I am getting 12-13.5mpg

I have and 02 Z71 with 4.10 gears and average right at 14mpg combined with no mods.  Pulls and accelerates great!

Many thanks for the advice on the 4.10.  Looks like a new Avalanche is in my future...if the incentives get just a little sweeter!!!

I have 03 with 410S, 373s shift way too much, drive you nuts if you are getting out of 410S. Sticker MPG is the same for both. I will never have anything but 410S. Love that off the line jump.

Mine was orphaned on the lot because it had a 4.10.  That was FINE with me.  Mileage seems around 15 - 16.  It's worth it.  You won't be sorry.

I also have an 02 with 4.10's. I have just over 100k on her now. I am averaging 20mpg on the interstate most of the time at 75-80mph. My best mileage was 26 driving between Rock Springs to Cheyenne Wyo. I have no idea how I did it but I was amazed. When I drive at lower altitudes like Wisconsin my mileage actually drops to around 18mpg at 75mph. If I drive the limit for that area and do 65 I can stay at 20mpg.

I drive to Cali about twice a year, and on the highway from Reno to Fresno I can pull 23mpg. I believe that is because the speed limit is only 55-65

So do yourself a huge favor and get the 4.10's. If you are unhappy i can guarantee someone on this site will take it off your hands.

I am currious to see a comparison article of all the different gear rations on the ave. I have an 02 Z71 with almost 140,000 on her now with the 3.73 gear ratio. Im also currious to see some video or something someone should do to show how much faster the 4.10's are off the line and in the long run. Maybe this is why in car and driver they say aves are like .4 seconds quicker to 60 than tundras and i lost to my buddy because car and driver never stated what gear ratio they used(assuming 4.10's). O ya and maybe a dyno run comparison of MPG between the two. Im getting 14mpg with about 65% highway. Mines rated at 13/17. How are you guys getting upwards of 20 im jealous! and i live in california

Gas mileage is increased or decreased by driving habits. I have learned to drive with my foot out of the gas for the most part, (sometimes I just have to floor it and hear my FM40). If you accelerate slower and try to stay below 2000rpm before shifting. Use cruise control whenever possible, I will use cruise control at 25mph on anything longer than a 1/4 mile. Plan your stops so you can start letting the truck slow down before using your brakes.
I also run Synthetic oil and check my tire pressures every week. Keeping your truck clean and waxed also helps.

I am from California and know that most of what I just typed is completely useless there. You are either hard on the gas or on the brake. You can't even drive to Vegas anymore using cruise.

Well I hopes some of this helps.

butterfingarz said:

I am currious to see a comparison article of all the different gear rations on the ave. I have an 02 Z71 with almost 140,000 on her now with the 3.73 gear ratio. Im also currious to see some video or something someone should do to show how much faster the 4.10's are off the line and in the long run. Maybe this is why in car and driver they say aves are like .4 seconds quicker to 60 than tundras and i lost to my buddy because car and driver never stated what gear ratio they used(assuming 4.10's). O ya and maybe a dyno run comparison of MPG between the two. Im getting 14mpg with about 65% highway. Mines rated at 13/17. How are you guys getting upwards of 20 im jealous! and i live in california

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No video but another member and I raced our Z71s at a 1/4 mile track, his truck with 4.10s was 1/2 second quicker than mine with 3.73s.
My speed was 1 mph faster because i was catching him at the end but since both our speeds were over 80 by then, 4.10s should translate into better highway performance and mileage than 3.73s.

I just switched from and 04 Z71 AV w/ 3.73's to an 05 Z71 Suburban w/ 3.42's.  According to GM literature the Sub. is a lighter vehicle by about 400lbs.  I figured I would get the same or better MPG in Sub.  Not the case.  On the highway the 3.42's seem just a tad too high for what the 5.3l likes.  At 70mph in the Sub. I am about 1850 rpm in the AV I think I was at 2000 or just above.  I think the sweet spot for the 5.3l on the hwy. is right about 2200.  With the 3.42's the tranny is in and out of OD alot.  In the AV I could get high 17 to low 18mpg on the hwy at about 75mph.  In the Sub. I get about 1 to 1 1/2 mpg less.  In town I dip into the 11mpg range which never happened in the AV.

That Sub must be slower off the line with the 3.42's compared to 3.73's or even 4.10's.
4.10's would be most beneficial for in town and towing.
3.73's would be better if you do more highway driving with not as much towing.
3.42's would be good for highway, but to tall for any kind of hills.

This is all just my opinion.

the 3:42 in my 05 Av Z71 is so lame it sucks heck a escort beats me of the line im going to upgrade my rear this spring to 4:10s ill live with lesser fuel mpg to have a real truck again 

butterfingarz said:

How are you guys getting upwards of 20 im jealous! and i live in california

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I beleive your problem is with the heavy traffic you deal with in Southern California.  My great gas mileage numbers were on open highway without traffic.  My best numbers were up and down steep mountain grades, in the horsepower using 2nd gear climbing and free mileage coasting down hill.  Between Las Vegas and anywhere in Utah I get better mileage in 3rd than in overdrive because the engine is in the powerband, closer to 3000 rpm in most cases, and because of the constance up and down grades the motor lugs too much in overdrive, between 1800 and 2200 rpm, below the powerband.

Back in the old days the manufacturers would show you a torque and horsepower graph to let you know where the engine made its best power.  It took me over 2 years to find anything on the internet that showed me the torque and horsepower graphs for the 2002.  And that info came from an aftermarket company showing before and after claims for its modifications.  Today the companies will only tell the peak numbers, and usually wont even mention what rpm's those numbers are measured at.

I get around 15.5 driving like granny with 3.73 gears and 265/70/17 tires

I agree on the open road I get 19-20. I drove 2200 miles in oct. from Coarsegold to Pocatello to Evanston who and back home. I find 4th gear is great for the entire trip. The only downshifting is when climbing Donner pass and a few mountains along the route. At 80 mph I am doing 2200 rpm. At 70 I am at 1850. I do have a BullyDog tuner and 285/70/17 tires. I run mid grade octane. I also have over 223,000 miles.

DIC right now says 15.5 mpg. My commute varies from 35 mph - 75 mph with some light traffic. Only time I can see 20+ mpg is if I reset the DIC during a long, flat stretch, and then I could see almost 25 mpg.....until I stick my foot in it. I tow a 5k lb ski boat regularly and the Av does it great. Guys on the boat forums Female Dog & complain about the 5.3 when they have the higher gears.