# General Motors 375 vs 410 rear end gear ?



## sea trout (Apr 21, 2016)

Any of y'all know alot about the differences....pro's n con's
to having one of these gears or the other behind a Duramax/Allison???
Me and my wife will be shopping for a used Duramax/Allison this early summer.
My knowledge consist of the 373 gear getting better hwy mpg than the 410 gear. And the 410 having more pulling power than 373 gear.
How much of a difference does these 2 different gear ratio's really make for fuel economy, pulling weight, and longevity of the drivetrain with daily driving and 2 or 3 times a month pulling???

Thanks for y'alls insight!!!!!!!!!


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## GoldDot40 (Apr 21, 2016)

If you're not using it more than just 3 times a month to pull, then go with a 3.73. The Duramax makes plenty enough torque to not need the 4.10 gears unless you we're regularly pulling a heavy trailer.


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## sea trout (Apr 22, 2016)

Thanks Bassquatch!
Were not hauling often but somtimes heavy. Our new boat is between 6 and 7 thousand. It will go on 5 to 7 hour trips a few times a year. It will go on 30 min and back trips a few times a month.
 A few times a year we haul our tractor. It's 3800 pounds naked in the spec book. Then add the weight of the bucket loader, antifreeze/water filled tires, 6ft bush hog, and 6ft box harrows and 18ft heavy steel trailer. Idk what all that weighs but it's very hard on my 2500 with small block gas motor and 373 gears.
Would that be easier on the truck with Duramax and the same 373 gear?? To last a long time? Thanks for advice man!!!!!!!!


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## lonewolf247 (Apr 22, 2016)

With the weights that you are towing, the Duramax with the 3.73 should be no problem. It should be capable of towing practically twice that much.  I'd recommend the 3.73 for that reason. You are not towing on a daily basis. However, if you happen to find a great deal on a truck with a  4.10 rear end, I wouldn't rule it out, but I'm sure the mileage will suffer a bit.


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## hdgapeach (Apr 22, 2016)

Don't know much about the Chebby's but, I'd have to also factor in which transmission (auto or manual).

IMO, the 3.73 would be OK with a stick.  I'm not familiar with the reliability of the automatics behind the Duramax.  I'd check into the reliability history of the auto trannys pulling heavy before getting one.

I've owned both gearing versions with the Ford 7.3 Powerstroke.  Both with manual transmissions.  Mileage difference was significant; 18-20mpg with the 3.73 and 13-14mpg running 4.10.  If I could hook to it, I could pull it with either of 'em.


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## lonewolf247 (Apr 23, 2016)

https://en.m.wikipedia.org/wiki/Allison_Transmission

http://www.allisontransmission.com


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## aabradley82 (Apr 23, 2016)

Seatrout, my dad has a 06 3500 with 375's and it has done ok except it's about the lightest duty dually we've ever had(or it feels that way.) Runs down the road good and pulls ok. My 14 ram 3500 seems about twice as stout. fuel mileage difference won't be huge, less than 2mpg. I'd go with whatever I found the best deal on.


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## GoldDot40 (Apr 23, 2016)

hdgapeach said:


> IMO, the 3.73 would be OK with a stick.  I'm not familiar with the reliability of the automatics behind the Duramax.  I'd check into the reliability history of the auto trannys pulling heavy before getting one.


The Allison transmissions GM uses behind the Duramax are likely one of the strongest and most reliable transmissions ever used in a production pickup truck.


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## lonewolf247 (Apr 24, 2016)

Bassquatch said:


> The Allison transmissions GM uses behind the Duramax are likely one of the strongest and most reliable transmissions ever used in a production pickup truck.




+1!!



aabradley82 said:


> Seatrout, my dad has a 06 3500 with 375's and it has done ok except it's about the lightest duty dually we've ever had(or it feels that way.) Runs down the road good and pulls ok. My 14 ram 3500 seems about twice as stout. fuel mileage difference won't be huge, less than 2mpg. I'd go with whatever I found the best deal on.



I agree that before the newer HD body style in 2007,  GM 2500, and 3500 offerings, were lagging behind as true heavy duty trucks.



hdgapeach said:


> Don't know much about the Chebby's but, I'd have to also factor in which transmission (auto or manual).
> 
> IMO, the 3.73 would be OK with a stick.  I'm not familiar with the reliability of the automatics behind the Duramax.  I'd check into the reliability history of the auto trannys pulling heavy before getting one.
> 
> I've owned both gearing versions with the Ford 7.3 Powerstroke.  Both with manual transmissions.  Mileage difference was significant; 18-20mpg with the 3.73 and 13-14mpg running 4.10.  If I could hook to it, I could pull it with either of 'em.



Years ago, Ford pretty much had cornered the market, in the diesel engine, and heavy duty categories.  They made a tough heavy duty truck, and had a good engine backing it up.

Dodge reached out to Cummins for help, and it ended up being one of the best decisions for them, as they quickly became a big contender in the heavy duty market. They had built a tough truck, and this diesel engine combination was making a name for itself. The only fault, I would give them is, their transmissions were having a hard time holding up to the torque delivered by  the Cummins engine.

GM on the other hand, while they made great half ton trucks, with gas engines, realized if they wanted to compete in the heavy duty, diesel engine market, they were really going to have to step up their game.

The Detroit diesel engines they offered were looked upon as inferior to consumer's,  so it was time to abandon that effort, and start over.  They ended up forming a partnership with Isuzu, and in 2001, they released the Duramax. 

Although GM was pretty successful in the automatic transmission market, they chose to go to Allison, the leader in heavy duty automatic transmissions, to make a transmission to back up the Duramax.  I think it was a great choice.  Although both manual and automatic transmissions were offered in the earliest Duramax, at some point, GM dropped that option, and only offered the duramax matched up with the Allison Automatic transmission. I'm not sure on the date. 

Since that time, they have really upped their game in making their HD trucks truly more heavy duty.  I think today GM is in the heavy duty market for real!

Bottom line, original poster, I think the Duramax/Allison HD truck, is a great choice, and I think either gear ratio, would serve you well for your towing needs! I actually have a 2015, 2500 HD with the 6.0 gas engine, and I can easily tow 10,000+ lbs, with no issues.


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## 95g atl (Apr 25, 2016)

Those weights you plan on towing are not bad even for a gas 1/2 ton Chevy w/3:73's.  
Towing regularly over 10k lbs, I would opt for the 4:10....otherwise, 3:73's will be better MPG and less noise on the hwy.


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## sea trout (Apr 25, 2016)

Thanks for all the input Y'all!!!
Yeah I haul all these things with 2500 gas.
My current 6.0 hauls the tractor and impliments...but not easily...according to me. It's hauled the new boat 4 times now (locally only but that will change), and its not as easy as I'm lookin for.

I think what I'm tryin to ask is, people who have hauled with vortec and duramax and both gear ratios, how much easier, if any, is the duramax at pullin a good load compared to a vortec 6.0. Then how much of a difference does the gear ratio make, which y'all have been anwerin thanks, ?

My 2011 2wd 2500 6.0 vortec with 3.73 say's the maximum trailer weight to be 9,600. Looking at the specs for duramax now that we're shopping for a used one claims 4wd duramax with 3.73 max trailer weight between 9 and 10 k. Same truck with 4.10 max trailer weight 13 to 14 k.
So with the tow ratings being the same on my truck and a duramax...I think what I'm askin is how much better will duramax pull 9-10k vs the truck I have now.
Am I still expecting to fight to keep 70-75 on I-85 or is 70-75 uphill not even gonna be noticable any more.
I know the sales people will tell me whatever I want to hear. So I'm wantin as much info as I can get!!!  
Thanks again so far gentlemen!!!!!!!!!!!!!!!!!!


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## T-N-T (Apr 25, 2016)

I had a 6.0 with 4 tens.  And dad has a duramax.  Made my truck seem so inferior. 
Dad's has the 3.73 I'm pretty sure.  And we have towed big loads.  No issues at all.  But he has a bully dog on it.  Set to fuel economy setting.  Still raises HP though.   But the Allison can handle a small bump just fine in HP.


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## T-N-T (Apr 25, 2016)

On a side note.  
I love my chevys.  Always have. They are home for me.
I now drive a cummins truck.  I'm might not ever go back either. 
The new 6.7s are tough.  Slower out of the gate.  But not by much.  The turbos need to spool up and the chevy just gets going right off. But it ain't really an issue.  I'll take the decades long proven reliability of cummins.


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## lonewolf247 (Apr 25, 2016)

sea trout said:


> Thanks for all the input Y'all!!!
> Yeah I haul all these things with 2500 gas.
> My current 6.0 hauls the tractor and impliments...but not easily...according to me. It's hauled the new boat 4 times now (locally only but that will change), and its not as easy as I'm lookin for.
> 
> ...




Your own example tells you just how much difference the gear ratio makes on the 6.0 gas engine. 3.73 =9,500lbs & 4.10=~14,000lbs. That's quite substantial!

In the current 2015-2016 year models, I don't even think 4.10 gear ratio is even an option with the Duramax. I'm not sure what year models that would have started with?

However, you cannot try to compare gear ratios between the 6.0 gas engine, and the Duramax diesel. There are too many different variables, with the different engines, transmissions, rpms, etc. So in other words, just because your 6.0 with 3.73 might seem to struggle a little at times, the Duramax with a 3.73 will be substantially different, and better. 

This is a chart of the 2015 2500HD trailering specs. In my truck configuration, the 6.0 gas with 3.73 is 9,700lbs, the 4.10 is 14,200lbs, and the duramax with 3.73 is 17,300lbs. I chose the 6.0 with the 4.10 and it tows fine for my needs, and the fuel runs between 13-17mpg empty, and never checked it towing. 

So, to answer your question, of how much better would the duramax do over the 6.0 gas with 3.73, in my example it would improve the towing by about roughly 8,000lbs!
The Duramax delivers a lot of torque!


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## lbzdually (Apr 27, 2016)

Duramax is only offered with 3.73's.  My dually with 3.73's has went up Monteagle many times grossing well over 20k lbs and never dropped below 50 going up in 4th gear. I can actually accelerate going up a 6% grade with that much weight if I want to.  A gas engine has nothing on a diesel for towing.


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## chadf (Apr 27, 2016)

I didn't read everything, but all from where I quite was spot on!

410 = higher rear end = more torque = more fuel

373 = lower gear ratio= less torque at lower rpms= less fuel for daily driving

* I've never owned a duramax or all full size, my $.02


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## Artfuldodger (Apr 27, 2016)

We went from a Chevy Astro 3:73 rear end to a Toyota 4Runner Sport with a 4:10. Even with a smaller engine it gets noticabilly less gas mileage.
I'm sure it will pull better. I miss the gas mileage of the 3:73.


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