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Expected fuel economy loss going from 3.21 w/ auto tranny to 3.73 w/auto tranny?

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Old Mar 31, 2013 | 10:27 AM
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Default Expected fuel economy loss going from 3.21 w/ auto tranny to 3.73 w/auto tranny?

Running 34 (295/75/16) Toyo AT/IIs currently and my JKU drives like a mule on the interstate. I can compensate around town shifting into manual mode but I really notice it accelerating as I merge onto the interstate as well as when I accelerate to pass. Driving into a 20-30 mph headwind last week wasn't fun either especially with my first experience with hood flutter. I am asking because I can get into a 3.73 equipped JKU with a few other goodies without taking a huge beating on my current JKU as dealer has offered $1500 less than what I paid and will sell new one for 1% under invoice. So for a net difference of $3500, I'll be picking up a hard top, 3.73 rear axle ratio, Alpine stereo, and anti-spin rear differential. I have read elsewhere that I am looking at around $1500 just to regear. Is it worth it? Advice/opinions appreciated.
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Old Mar 31, 2013 | 10:34 AM
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I wouId do it and not think twice!
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Old Mar 31, 2013 | 10:39 AM
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i doubt there will much difference in mpg one way or another. If you want a hardtop, probably not a bad deal because if you have yours regeared you risk having gear whine if not properly installed and there are installers who will tell you that is normal but pretty rare from the factory. figure the hardtop is going to be hard to pick used for a decent price and stereo and anti-spin are nice upgrades. all and all sounds decent.
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Old Mar 31, 2013 | 11:24 AM
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Go for it, the 373 is way better than the 321. IMO
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Old Mar 31, 2013 | 02:58 PM
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Go with 373's I'm getting 19 mpg on state roads from 35 to 55. 16 mpg 55+ all the way to 80 mph. In town I'm getting 15 to 16 stop and go.
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Old Mar 31, 2013 | 07:53 PM
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Thanks for everyone's advice/replies. Seems like a "no brainer." Now the question, stick with the same color I have now (deep cherry red crystal pearl) or go with the bright white? Both are Unlimited Sports. Both have pretty much the same equipment.
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Old Mar 31, 2013 | 08:22 PM
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Just out of curiosity but did you use a procal to recalibrate your shift points? I have two door and I'm looking at Nitto Trail Grapplers in 295 70 17. Manufacture site says 33.5 x 11.97. You now have me concerned it'll turn it into a slug lol. I have 32" Bfg Kms now.
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Old Mar 31, 2013 | 08:47 PM
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Originally Posted by Chrislh
Just out of curiosity but did you use a procal to recalibrate your shift points? I have two door and I'm looking at Nitto Trail Grapplers in 295 70 17. Manufacture site says 33.5 x 11.97. You now have me concerned it'll turn it into a slug lol. I have 32" Bfg Kms now.
Yes, I did buy a procal and did recal. the shift points. Better than with the original shift points but still a little sluggish. Could I make do? Probably since I live where it's flat and I don't mind using the auto in manual shift mode. From what I'm experieincing and reading, 3.73 will be much better. I hope.
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Old Mar 31, 2013 | 10:03 PM
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$3500 for a hardtop, new gears, LSD, and slightly better stereo... seems like a rip off to me. For $3500 you could probably regear and get lockers.
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Old Mar 31, 2013 | 11:31 PM
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Originally Posted by hypeiv
$3500 for a hardtop, new gears, LSD, and slightly better stereo... seems like a rip off to me. For $3500 you could probably regear and get lockers.
I would agree - I say use the 3500 to invest in the one you have. Does the new one come with tires? That's another $1200 you will need to invest. Also, going from 3.21's to 3.73's with 33/34's will not be a significant difference. I did it and regretted it and now with 4.56.

Dont let "New to you..." get you - save the money and make your rig even better.
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