[texan_z71]

I am running a 3.08 gear ratio with 35 in tires and i get about 10.5 mpg combined with 50%-60% of the miles on the highway. This just doesn't seem right for a 2011 1500 5.3L Silverado. I plan to be getting 100K more miles out of this truck and I am considering re-gearing because even a 2 mpg gain would save me money in the long run. What gear should I go to in order to get the best MPG out of my truck. I don't tow often and if I do it wouldn't be much at all.

 

[ASTE25]

I think you would do better by regearing since you are running that large of a tire. 3.08's are a pretty high gear ratio for that big of a tire and that large of a truck. I'd suggest going to 3.73's. This is going to look like I said this to sell my part, but check this out: 1500 front differential This would take care of half your problem (if you decide to regear you will have to change the front and back to the same ratio).

 

[09chevyman]

I agree with the above^^^ but you should also consider 4:10's. They would give you a little more get up & go and shouldn't be to low to hurt mpg's at higher rpm's..either change would be a drastic change from what you have now for the better overall performance of your truck...

 

[texan_z71]

Thanks for the reply, I gave my mechanic (good guy with low prices) a call asking for a quote for just labor, hes gonna get back to me about it tomorrow. I plan on just changing the gears right now, but if that turns out to be something wrong with my transmission I may just have to get that from you. Do you think I should get the 3.73 over the 4.10? I'm not trying to keep a similar gear ratio to the 3.08 but would just want the best one for 50/50 city and highway, with light towing and offroading

 

[texan_z71]

didn't see you posted before me chevyman. Ya i would like my truck to feel more like a truck and less like a, shall we say ford ranger... What kind of mpg change do you think I could see with either the 3.73 or 4.10 since im only getting 10-11 combined right now

 

[wildchevy]

I'd go with the 3.73's just in you want to go smaller on the tire someday, remember those 35's are hard on everything in a 1/2 ton.

 

[09chevyman]

Hopefully you could see anywhere from 12-14 mpg's or more...maybe...and 3:73's will work but only if your talking very light towing. I would say nothing more than 3-4000 pounds if more go 4:10's..

 

[ASTE25]

Well, I will have to say, if it were me and I was going to have to pay to have the install done, I'd prolly go with the 4.10's. Just to let you know, what I have listed for sale is the front differential, not the transmission. If you decide to go with 3.73's the front differential I have is complete and brand new. I think you would save money by installing it since it requires a lot less labor to install rather than having to buy the gears and other parts +labor to have 3.73's installed in your front differential. I had bought it to replace the 3.42's my 2012 had, but I traded that in on my 2013 2500 so I don't need them anymore.

 

[texan_z71]

I don't plan on using anything less than 35's on my truck so I may go with the 4.10's that way towing isn't thrown out the window.

ASTE25, I don't know hardly anything about how the transmission/differentials work, but what your selling is what the gears are in?

 

[ASTE25]

Yes, it is a complete front differential assembly. It is brand new. It includes everything you would need to change your front gears to a 3.73 ratio (except you would have to buy a couple of bottles of gear oil to put in it because it has no oil in it right now). Whichever way you decide to go, you will have to regear both the front and rear differentials to the same ratio to be able to use your 4WD. If you don't, you will seriously damage the drivetrain if you use it in 4WD without having the same gear ratio in both differentials. The good thing about using this would be that you could sell the one you take out and make some of your money back.

 

[texan_z71]

i'm looking forward to see what my mechanic says it'll be for labor. I'll keep this thread updated with what I am deciding and if I want to buy that

 

[ASTE25]

No pressure, I've had it for sale a while.

 

[texan_z71]

the longer you wait the more customers on the market lol

 

[ASTE25]

Here is an idea of what it would cost (in parts) to put 3.73's in your front differential:

http://www.4wheelparts.com/Drivetrain-D ... 1-2095-373

http://www.4wheelparts.com/Drivetrain-D ... 2f235-2095

You may need this since you are going from a 3.08 ratio:

http://www.4wheelparts.com/Drivetrain-D ... 2f265-2095

You may be able to find better prices, I just did a quick search to let you know what all is involved in changing out gears. This does not include labor.

 

[texan_z71]

thanks for looking man

 

[linkman440]

I have 35's and 3.73 gears. I get about 11-13 mpg. But I've got no get up and go. I also do have the 4 speed trans. I'm thinking of going to 4.56 gears to make up for it. If you find one of those ratio calculators it'll show you what gear you need to put it back close to stock

 

[texan_z71]

going from stock 31 in to 35, a 4.10 with 35s is like 3.63..which seems like a good ratio

 

[mfdrookie516]

There's a big difference in the first gear ratio of a 6 speed compared to the old 4 speed. The same truck with a 6 speed will have a lot more get up and go. 373's are going to be closer to your stock setup than 410's, and IMO will net you better fuel economy, but that's just my opinion of course.

 

[rdmorgan05]

I'm thinking of going to a 33" tire when my tires need replacing maybe a 33.5". I have the old 4 speed tranny with 3.42's. Also it's 2WD... Should I go 3.73's, 4.10's, or just stay where I'm at?

Sent from AutoGuide.com Free App

 

[texan_z71]

There's a big difference in the first gear ratio of a 6 speed compared to the old 4 speed. The same truck with a 6 speed will have a lot more get up and go. 373's are going to be closer to your stock setup than 410's, and IMO will net you better fuel economy, but that's just my opinion of course.

If talking about a completely stock truck, would you say the 3.42 are the best gear for gas mileage or the 3.73?