changeing rear end gear ratio - Diesel Truck Forum - TheDieselGarage.com
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post #1 of 7 (permalink) Old 07-08-2007, 04:41 PM Thread Starter
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changeing rear end gear ratio

my brother is looking at buying a 01 to 04 2wd 2500 with a 6 speed and duramax, and is gonna try and see how much fuel economy he can get out of it. he is wanting to swap in a different set of gears around 3.08's but we are having trouble finding any or even what rear end it has. I know the gear vendor is an option but its a bit pricey and he wont be pulling any big loads so the taller gears wont hurt any thing

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post #2 of 7 (permalink) Old 07-08-2007, 07:17 PM
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3.73's were standard on Dmaxs. I think the only gear options out there are 4.10s.

He could put 285's on the truck to lower the ratio, too. Dont know if it would help mileage, though.
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post #3 of 7 (permalink) Old 07-08-2007, 08:45 PM
 
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I believe the d'maxs all came w/ the GM11.5" rear end. Don't know if there are to many ratios availible though.

I would just put on taller tires to effectively increase the ratio.

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post #4 of 7 (permalink) Old 07-08-2007, 09:39 PM
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Diesels are work engines, built and intended to pull heavy loads efficiantly. If he wants good economy out of a diesel, then tell him to buy a VW with a TDI. Those cars get around 40-50MPG. A GM truck is nothing more than a big wind break with a strong engine, not really a economical truck by any means.

Just my .02,
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post #5 of 7 (permalink) Old 07-08-2007, 10:23 PM
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No one makes anything lower than a 3.73 for the AAM 11.5 14 Bolt. Its from 3.73-5.13 for that axle.

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post #6 of 7 (permalink) Old 07-09-2007, 12:29 AM Thread Starter
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Quote:
Originally Posted by Horsehaulin
Diesels are work engines, built and intended to pull heavy loads efficiantly. If he wants good economy out of a diesel, then tell him to buy a VW with a TDI. Those cars get around 40-50MPG. A GM truck is nothing more than a big wind break with a strong engine, not really a economical truck by any means.

Just my .02,
Tony
he will be pulling a light load every now and then so heed needs something more than a small car or pickup. he isn't expecting 40 to 50 mpg just hoping for mid 20's
we thought a different gear ratio would be an easy change that might make a big difference but if nothing taller than 3.73's is available he can probably get decent fuel mileage out of it without it.

Ross
Show-ME Smokers 2.6 modified street pulling truck "The Lone Stroke" My Videos
1996 f350, powerstroke, 4x4, 5-speed, 4.56 gears, Swamps 450/600 injectors, Swamps BFH turbo, Swamps Idm, Swamps tunes, BTS oil, SBC clutch, studs, springs, tubes, air to water intercooler, fuel system, factory rods!


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1997 f350, srw, reg cab, 4x4, 5 speed, 4.10 gears, 3in down pipe, straight pipe, mystery chip.

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post #7 of 7 (permalink) Old 07-11-2007, 04:51 AM
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I gotcha, I didnt realize he was going to use it to tow with at times. That makes sense. I wasnt trying to insult him, but I think he should get around 20MPG with a DMAX. My neighbor gets 22-23hgwy. Hes got a few mods, but nothing like EFI Live.

Tony

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05 IH 9400i with Cummins ISX pulling a lumber bunk trailer, stuck in a swamp somewhere in Indiana.

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