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Old 01-16-2014, 12:55 PM   #1
mmmdaddy57
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Default Rear end upgrade

I have a 2000 Mustang 3.8 with 7.5 rear end 3.27 gears. I would like to know what years are direct crossover to a 8.8. I would like to put in a 8.8 posi. with 3.08 gears. I think I have read before that any 8.8 from 94-04 will work, but I would like that verified.
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Old 01-16-2014, 02:17 PM   #2
Derf00
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94 to 2004 should drop right in... Why 3.08 though? that's really low (slower) than the 3.27 you have. If anything you should be looking at 3.73 or even 4.10 if you're an auto.

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Old 01-17-2014, 06:04 AM   #3
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I do not believe you can get lower than 3.27 for mustangs from 99-04, 3.27 was the lowest you could get already. From the factory anyways.

You could always have a shop install something else but going with a lower number is gonna give you worse fuel mileage as the car will have to work harder to get up to speed.
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Old 01-17-2014, 08:39 AM   #4
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I do not believe you can get lower than 3.27 for mustangs from 99-04, 3.27 was the lowest you could get already. From the factory anyways.

You could always have a shop install something else but going with a lower number is gonna give you worse fuel mileage as the car will have to work harder to get up to speed.
Actually the 3.08 is slightly better fuel economy than the 3.27. Due to less rpm for a given speed. The higher you go up in gears the worse your fuel mileage gets. Since 55mph at 1600rpm is better fuel mileage than 55mph at 2000 rpm.
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Old 01-17-2014, 11:54 AM   #5
mmmdaddy57
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My 1998 had 2.73 gears and I liked the fuel economy.(combination driving around 24 mpg 27 on the highway). I'm not drag racing it. but I do like to go around corners (with control) and cruise on the highway I installed the Eibach lowering kit with springs, front and back, rear control arms, sway bars, KYB shocks. There where no rear sway bars originally on mine. I also added wheel extenders to bring the 235/40/18 wheels out further, 1.5" in the rear and 1" in the front, which also keeps the tire from hitting the rear inner fenderwell and the sway bar in front. With everything installed the difference is substantial. I installed duel exhaust and will be putting in a CAI on my 3.8. For me the 3.8 has plenty of power for windy roads (I live in the foothills with lots of windy roads. When I travel down the hill its all straight and flat.
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Old 01-18-2014, 08:28 AM   #6
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Actually the 3.08 is slightly better fuel economy than the 3.27. Due to less rpm for a given speed. The higher you go up in gears the worse your fuel mileage gets. Since 55mph at 1600rpm is better fuel mileage than 55mph at 2000 rpm.
I know what your saying, but in stop and go traffic, your going to have to get on it harder to get going which will use more fuel.
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Old 01-19-2014, 11:16 AM   #7
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Quote:
Originally Posted by BabyGT View Post
I do not believe you can get lower than 3.27 for mustangs from 99-04, 3.27 was the lowest you could get already. From the factory anyways.

You could always have a shop install something else but going with a lower number is gonna give you worse fuel mileage as the car will have to work harder to get up to speed.
A very few 99 and 00 GT autos came with 3.08 gears, most 94-98 were 2.73 but you could get 3.08 or 3.27 as well. I am allways against swapping rears because the 8.8 is heavier and you don't know what kind of life it had had, I would recommend rebuilding your 7.5 with your choice of gears, a Detroit true trac or eaton LSD, and a Bering kit and never have to worry about it again.
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Old 01-19-2014, 12:11 PM   #8
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I agree as far as building something to last BUT part for the 7.5 are usually a bit more expensive due to low demand. And we can't all afford it lol.
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Old 01-19-2014, 01:49 PM   #9
mmmdaddy57
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I could put in a tru trac and new gears but Its cheaper just to find a 8.8 that will cost about 300.00 and will bolt right in already done. It looks like it would cost over 800.00 at summit to install a new carrier, gear set and install kit

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Old 01-20-2014, 06:52 PM   #10
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Quote:
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I agree as far as building something to last BUT part for the 7.5 are usually a bit more expensive due to low demand. And we can't all afford it lol.
I agree its more expensive at once, but how much of your time (which is still worth money) do you want to spend swapping 2-3 rear ends out due to issues, or swapping in an 8.8 just to rebuild it any ways? I guess it depends on what your over all plans for the car are
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