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  • avatar karjunkie 11/15/08 10:10 am PST

    Unless you plan on doing a lot of highway driving, the difference won't be significant. In fact, some vehicles get slightly better in-town mileage with a higher axle ratio, because the engine load is reduced slightly.The best you can hope for is maybe 1 MPG improvement on highway only. Your gas mileage is going to suck no matter what, so you might as well get a little more acceleration with the 3.73 axle. If fuel economy is a major concern, a full size 4X4 pickup that weighs almost three tons isn't your best bet. I have seen that the new higher revving SB Chevy engines actually work better with lower ratio rear ends, 3.73 and even 4.10's get better mileage than 3.42 rear ends because the engine is in it's zone, as far as RPM.

Answers

  • karjunkie 11/15/08 10:10 am PST

    Unless you plan on doing a lot of highway driving, the difference won't be significant. In fact, some vehicles get slightly better in-town mileage with a higher axle ratio, because the engine load is reduced slightly.The best you can hope for is maybe 1 MPG improvement on highway only. Your gas mileage is going to suck no matter what, so you might as well get a little more acceleration with the 3.73 axle. If fuel economy is a major concern, a full size 4X4 pickup that weighs almost three tons isn't your best bet. I have seen that the new higher revving SB Chevy engines actually work better with lower ratio rear ends, 3.73 and even 4.10's get better mileage than 3.42 rear ends because the engine is in it's zone, as far as RPM.

  • wingwlkr 11/16/08 7:14 pm PST

    Thanks for the reply karjunkie. Wow, I'm impressed; 9680 points. Very impressive.



    Anyway, what made me wonder about the finial drive ratio on the truck is my experience with my two cars. I have two Saab 9000's, that are both 5 speeds, and have the same 2.3L engines. Because of different years, the final drive ratio is different. One turns 3200 rpm at 75 mph and gets 26 mpg. The other car turns 2600 rpm at 75 mph and gets 31 mpg.



    I was wondering if the truck would behave similarly, but what you said about the engine being in its sweet zone makes sense.



    Also, like you said, I'm not buying a truck this size for mileage, but to do a job. I do use it as a work truck, and not a cowboy Cadilliac.


    I want a Quadrasteer, but do not tow a trailer. I Figure that if I could get a 3.73, or 3.42 rear end, gas mileage would be a bit better. Of course driving a full size truck is not about gas mileage, but it doesn't hurt to save where I can.

    Does anyone know if the Silverado Quadrasteer came with only a 4.10 rear end.?

    Regards, and thanks again for the prompt reply,



    Ed

    Source: 

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