Chevy rear end ratios

[Eltonnoland]

I've been looking at new and used Chevy 2500's and want a 6.0 gas. As I understand it, a 4.10 is the only rear end offered on a 6.0. Using the codes in the glove box I've noticed a lot of 2013's and older have 3.73. Did Chevy change what they offered? How much is a 4.10 going to affect mileage when not towing? I'm presently towing with a 5.3L and 3.42 gears and have no problem with a 6800lb dry load TT. Just trying to remove the suck and blow.

[AquaMan]

Originally Posted by Eltonnoland

I've been looking at new and used Chevy 2500's and want a 6.0 gas. As I understand it, a 4.10 is the only rear end offered on a 6.0. Using the codes in the glove box I've noticed a lot of 2013's and older have 3.73. Did Chevy change what they offered? How much is a 4.10 going to affect mileage when not towing? I'm presently towing with a 5.3L and 3.42 gears and have no problem with a 6800lb dry load TT. Just trying to remove the suck and blow.

I had a 2006 2500 with 6.0 and 4.10 gears. In that year, I'm pretty sure a 3.73 was also offered, but it also only had 4 speed tranny. With the newer 6 speed transmissions, you should do better with highway mileage unloaded and have better pulling power when towing. I believe the 6 speeds and the improvements made to the 6.0 made the 3.73 somewhat obsolete, that's why it was dropped.

[TURBS]

I had a 2005 2500 HD 6.0 with the 410 gear.
Driving unloaded I averaged about 13-15 mpg
loaded with camper 9-10 mpg.



Turbs

[elind]

This spring I was looking at a 2014 Chev 2500 / 6.0. GM has both 3.73 and 4.10 rear ends, but the 4.10s are hard to find. The 4.10 affects GM's overall fuel mileage so they put the 3.73 out there instead. The 3.73 tow rating is only about 9,500lb and the 4.10 was 12,000-13,000 lb. And of course the gas mileage is different.

[Eltonnoland]

GMC doesn't offer 373 in 2015. They may have in 2014. That's good to know.

[KenHwy61]

I have a 2012 chevy 2500HD with a 6.0 gas and 3.73 rear end. I could be wrong, but I was under the impression the 4.10's are hard to come by after the 6 speed auto came out. In any case, I pull a 9-10,000 pound trailer confidently with this truck and average about 9mpg.

[Eltonnoland]

What are you getting without a trailer?

[elind]

I had to buy a Duramax because there wasn't a 4.10 within 500 miles of me. But now, I do love the D-max.


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[elind]

I get 17-23 unloaded with the Duramax and 11-12 pulling the 5er@ 12,000lb


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[KenHwy61]

I get about 14 combine city/highway mpg which is 2.5 mpg better than my 2004 6.0 got. This truck also is more stable and stops much better than my '04

[muddyrode]

your milage will only change from .5 to 1.5 depending on how you drive but you will gain an extra 4000# tow rating with the 4:10's, i know guys with both a 4:10 in a 2015 and the 3:73 in a 2013 not much differance unless you are going to do a Lot!! of hiway driving without a trailer
i can get 19+ hiway with my Duramax and would never go back

[davel1971]

I had a 09 GMC 2500 with a 6.0 and 3.73s and was getting about 7-8MPG towing 8000 lbs., about 13MPG not towing. Now towing 11,500 lbs with a Duramax and getting 12MPG, 20+ not towing.

[WFD]

I have a 2011 2500HD with the 6.0L and it has the 3.73....the 4.10 was pretty hard to find. I didn't really want the 4.10 so coming across the majority of used 2500's with 3,73 suited me just fine. Talked to a couple dealers and they were telling me they were pretty much just bringing them in with 4.10's on a factory order.
My main reason was due to the majority saying mileage would suffer with 4.10's when not towing, which would be about 80% of the mileage I do, so I didn't want to chance it and find out.

[MillerTime]

Originally Posted by Eltonnoland

I've been looking at new and used Chevy 2500's and want a 6.0 gas. As I understand it, a 4.10 is the only rear end offered on a 6.0.

This is correct. (For the U.S. other countrys may get different options)

If you get a 6.0 in a 2500hd or 3500hd you can only get 4.10

If you get the 6.0 in a 1500hd or 2500 (no hd and no longer offered) than you could get 3.73

If you get the duramax in anything (except 4500 and 5500) from day one, from the '01 on, you can only get 3.73 gears.

5.3 has the 3.08 and 3.42 in the 1500 and you can get the 3.73 with the 6.2 in the tow max package (prior to the 6.2, it was the vortec max and had the 6.0.)

4, 5, or 6 speed trannys, this is how the gearing has been on the hd line up, unless someone had the gears changed (the 1500 non hd trucks have had several optional gear/package changes since the '99s came out.)
Any question on your ratio, send me you Vin and i can run it at work, or you can just find the gear option code in your glove box.

Seems like we went thru this about a year ago on here.

[Eltonnoland]

Thanks for your reply. Has the 2500 HD ever been offered with the 3.73?

[davel1971]

Originally Posted by Eltonnoland

Thanks for your reply. Has the 2500 HD ever been offered with the 3.73?

yes, my 09 GMC was

[WFD]

Like I mentioned in post #13....my 2011 has 3.73.

[smittyams]

If your talking gas mileage, I've got an 01 GMC 3500 dually diesel and I'm getting upper teens lower twenties on the highway. That's an old big truck to get that kind of mileage and towing mileage is better than any gas.

[MillerTime]

Sorry i must have missed a few years there.
The 01-07 were like i said and the past couple years were that way on online ordering. Maybe you could order different in person or for different regions??
Sorry about the confusion. Heres some common rpo codes that you can look for

[Backcountry]

I have a '01 2500HD with a 4.10 and the vast majority of the older ones I shopped were that, although I did see a few 3.73. I don't think it really makes any more than a marginal difference in gas mileage but it does make a big difference on how much you can tow with it so make sure you do your homework. If you're thinking you'll save gas by jumping down to a 3.73 I wouldn't personally do it if you're planning on using it as a tow vehicle.