3.08 to 3.73

[silveradosid]

i have a 2014 5.3 4x4 ccsb with 3.08 gears. i can get a front and rear diffs from a 2014 with 3.73 . i do almost all highway miles and would like to know if this is worth the effort. i do pull trailers ocassionally how much will it effect my gas mileage

[Black02Silverado]

To me it would not be worth it.  You would take a nice hit on MPG. 

 

Unless you are going to install a lift and bigger tires there wouldn't be any need to go that high on a gear ratio.

[aseibel]

That gear change would make your driveshaft turn 20% faster than it currently does.

 

That does not translate directly to MPGs increase. But while in drive, your engine rpms will still be significantly higher.

 

Unless you NEED the torque for towing, I think this change would be a waste of time & money.

I'd look for a new truck before I spent money on changing gears.

 

Like Black02Silverado said, unless you are trying to turn much larger tires while maintaining the current pep of your ride, its not worth it.

[silveradosid]

i can get both diffs for 600 buck and yes would be going to larger tires

[Black02Silverado]

Just now, silveradosid said:

i can get both diffs for 600 buck and yes would be going to larger tires

That sounds to good to be true for the cost.  Make sure they are good and there is no problems with them. 

[silveradosid]

from a burnt truck trying to figure what size of tire to achieve the same as 3.42

[cr250Silverado]

Stock 3.73's only came in the 9.76 rear Axel, and you have 3.08s so you have a 9.5 rear axle.  So unless you are swapping out the entire Axel I *don't know* (but I highly doubt) the carrier/gears will be compatible with your Axel. If I were able to get my hands on that I would probably buy the entire rear axle assembly and the complete front carrier.

[silveradosid]

it is the entire carriers and it looks like if i go to a 275/70-18 i would end up at the same rpm's as 3.42

[Nasty]

1 hour ago, Black02Silverado said:

To me it would not be worth it.  You would take a nice hit on MPG. 

 

Unless you are going to install a lift and bigger tires there wouldn't be any need to go that high on a gear ratio.

This all depends.  My truck came stock with 342 and the 275 55 20 (31.8 tall)

 

Im now running a 275 45 20(29.5)  and i average better mpg.  Thats not a huge gear change but depending how you drive it should stay around the same.

[silveradosid]

275/70-18 would be a 33 just trying to figure if a 33 is going to kill my gas mileage

[300 Blackout]

Since 3.73 is a OEM gear ratio, the dealer should have plenty of info about your expected gas mileage. You should also ask them if they are willing to update your computer for that gear ratio, otherwise you will need a tuner or similar device.

My opinion, without bigger tires, I don’t think you’re looking at a huge difference in gas mileage. Driving habits will likely have a bigger impact than the gears. With 3.73 you’ll likely enter V4 earlier than with the 3.08 so it may equal out to a minimal mpg difference.

If you do put bigger, heavier tires on, it’s hard to say how much of a change you will see since there are a lot of variables. Tire tread, weight, width, circumference, etc... that all will have an impact on your fuel efficiency.

I have 33.5” tires. Each wheel/tire weighs 115lbs. This dropped me down to 12mpg with 3.42 gears. I installed 4.56 gears and it went up to 15.3mpg with 87 gas. During average around town and highway driving, it’s in V4 more than 50% of the time (probably closer to 75%). Highway mpg on 87 gas appears to be around 19mpg.

[Jon A]

On 10/8/2018 at 5:39 AM, silveradosid said:

would like to know if this is worth the effort. i do pull trailers ocassionally how much will it effect my gas mileage

Being worth the effort is, of course, in the eye of the beholder.  But in my opinion, absolutely it will be worth it.  If you can get the parts for that price, they're in good shape and install/set them up correctly it's a fantastic deal that will make the truck more enjoyable to drive, especially when towing.  Even more so when you add larger tires.  Most here who have a shop install gears pay $2000+ for it (even without new carriers) and typically say it was one of their favorite mods and definitely "worth it" even at that price.

 

I would expect the mileage changes to be negligible.  You'll take a hit with the larger tires with either ratio.  With larger tires there are many scenarios where the 3.08 gears become more of a hindrance than a help.  If you want the best mileage with larger tires, try and stick to lighter weight/lower rated (P-rated) tires.

[Centex14]

Gears are one of the best things you can do. I find the factories way under gear vehicles regardless of the make.


2014 z71 LTZ
Volant Intake
Borla Exhaust
Diablo
Bilstein 5100
Rough Country Level

[silveradosid]

300 blackout what tires do you have i was thinking bfg k02

[300 Blackout]

300 blackout what tires do you have i was thinking bfg k02

Cooper STT Pro 275/65R20. The K02 is a great tire also.