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Long time reader, first time poster...


I noticed that 4.11 gears are now available with the '04 Duramax. I have looked everywhere and can only find tow ratings for the Duramax and 3.73 gears with no mention of 4.11's. Any thoughts on how the new LLY power, torque and RPM curves would jive with 4.11 vs 3.73 gears for towing, mileage and performance?


I have 3.73 gears in my '03 GMC D/A 2500HD and it does just fine pulling my 12,000# fiver and get's around town nicely as my daily driver. I just wrote an order to upgrade to a GMC D/A 3500 Dually and chose 3.73 gears and still have time to call my dealer and change this.


Thanks!Edited by: Wimpie
 

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Makes no sence to me .... Lower gear ratio will result in higher rpms ,which will resort to lower fuel econo ... It will change the performance and but the gains will be less then what you'll lose in my opinion ...Imagine your econo empty 70ish on the interstate,or even light towing ...


It's a diesel lower gear ratio IMO isn't needed the low end torque is already there ....There already lowering the peak torque at rpm so it apears to me....


To me it's only going to help the people instaling bigger tires ...


Mac
 

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The 3500 have smaller tires than the 2500 HD so unless u are going to go 265/75 on the 3500, I'd stay w/ the 3.73.
 

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The 4.11 will be a very nice option for those who lift and put the big tires on there trucks. With 35 inch tires the 4.11 is very close to 3.73. Edited by: ripper
 

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I'd be surprised if GM is offering the 4:11 ratio for the big-tire guys since they've been screaming about larger tires voiding warranty, etc. for the last couple years. Unless of course, they think they would sell more trucks (and they would) if they wouldn't get so nit picky about larger tires or moderate lifts.


I would love to have 4:11's today.
 

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I think they will only be available with the 3500 SRW running 265/75-16
 

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4.1 ratio rears have no place in a Duramax equipped truck. No matter what your using it for.
 

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I just special ordered a 04 2500HD CC LWB 4x4 with D/A. The dealer said no to 4.10's with the Duramax in the LB7 or LLY. I had the choice of what engine I wanted though. I plan on doing a lift so the 4.10 would have been just what I needed. I even called GM.
 

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CPMac said:
4.1 ratio rears have no place in a Duramax equipped truck. No matter what your using it for.
Care to explain you reasoning? 4.10s would be great for all these guys running 35" and larger tires.
 

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y2kboti said:
CPMac said:
4.1 ratio rears have no place in a Duramax equipped truck. No matter what your using it for.
Care to explain you reasoning? 4.10s would be great for all these guys running 35" and larger tires.

Kind a what I was thinkin ... for me they would restore the stock-like gear ratio, make allison shift where it use to, etc. In the end the re-gearing would be like fooling the truck into thinking it had the donut 245's installed again.


If I used the truck to pull stumps out of the ground for a living I would think lower gears would be a good thing... perhaps not?
 

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tophog said:
If I used the truck to pull stumps out of the ground for a living I would think lower gears would be a good thing... perhaps not?

Trust me, 4X4LO works really well for the big stumps.



Some smaller stumps don't even require 4X4HI.
 

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Did GM do something to the Allison to accomadate the 4.11.
 

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If I pulled a big trailer 4.10's with my 35's would be great. No power programmer will make a higher reving engine pull at low rpms as well as keeping the r's up. If they were available 3.90's would give a perfect balance with big tires.


Bill, 496's come with 4.10's and the Allison. I'm not sure if the torque converter is different but other than that it's all in the computer.
 

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I agree with y2kboti, everything I've read says no 4.11's on the Duramax, but I also hadn't heard anything specifically on the SRW 3500 Amric, interesting anyway.
 
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