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Old 01-05-2011, 08:11 PM   #1
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456 over 392

I have 3.92 now with 305/45/r22 an i get 13.4 mpg would 4.56 make milage go up an would power b noticable improvment or better to leave alone

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Old 01-05-2011, 08:26 PM   #2
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My truck has the factory 20s and when I went from 3.92 to 4.56 I gained some mileage around town and lost some on the highway. The difference in off the line acceleration is like night and day.
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Old 01-05-2011, 10:18 PM   #3
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356s would help you get better mileage in town, tow better, quicker acceleration, spin the 305/45/22 tires easier, have less of a strain on the not so strong trans. Yes, highway mileage will be affected above 70mph. The trade off to me was one of the best mods I did to my truck. I have the same size tires.

PS. Get a Sonnax line pressure booster for the trans. Every little bit helps with 545RFE trans. A smart investment.
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Old 01-06-2011, 01:40 AM   #4
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Go 4.56 and don't look back. Huge improvement in city driveability.
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Old 01-06-2011, 08:53 AM   #5
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With all of the above.
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Old 01-06-2011, 09:33 AM   #6
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Old 01-07-2011, 09:06 PM   #7
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do the 4.56 you will not regret it.i drove from NY to Ohio and i was getting almost 19 miles a gallon at 75 - 80 mph
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Old 01-08-2011, 04:10 AM   #8
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I'm running 30.5" tire and went with 4:10 and wish I had gone with the 4:56.
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Old 07-16-2011, 06:21 PM   #9
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456 over 392

An old thread I know but another question about gears. After an upgrade to 4.56 gears, what is the difference in driving in overdrive all the time; or only using it on the highway? Are you in a different ratio in overdrive [.067] say 3.06 or 4.56 either way? Sorry for my ignorance!!
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Old 07-18-2011, 10:08 PM   #10
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Anyone have an opinion or explanation? Sorry again for my ignorance
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