3.55 worth it?

[1320']

All autos are 3.15 by default unless replaced with 3.55s

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[Spartan]

Everyone has a personal preference to which gear set to chose.

If you plan on leaving the car stock, definitely go with the 3.55's. it will feel snappier.
If you plan on modifying the car, 3.15's or 3.55's will work.

In regards to mileage... I still manage to get 18mpg from my daily driven 94 F150 with a 5.0 HO,Automatic, 3.55LS with 260,000 miles on it... so don't let people tell you that you'll lose more than 2-3mpg depending on how you drive.

I'll have a used 3.55 ratio factory set available soon (26,000 miles on them)
changing to 4.88 ratio

Well if you check the MPG thread there seem to be lots of autos with 3.55s getting nice highway mpg still...somewhere in the 26-28 range...their city is around 18ish I believe.

 

[1320']

3.55 is actually a bit too much gear for the auto.

I wish Ford had offered 3.31's as the performance gear option

 

[neodark]

That was a typo on the original guides. The Autos get 3.15s unless you order the 3.55 package (or get the PP which is 3.77).

Page 17
http://www.mustang6g.com/forums/showthread.php?t=22880

All autos are 3.15 by default unless replaced with 3.55s

I would agree with you. However, we did some research and the actual sticker on the differential indicates 3.31s. Here's a picture of mine, premium EB... Non PP. My window sticker does not show them as an option.

If you look at the sticker closely you can see 3L31 or check this thread for details on the meaning of it: http://www.mustang6g.com/forums/showthread.php?t=20815&page=4&highlight=differential

 

[1320']

It's because yours is an EcoBoost, base EcoBoosts get 3.15's or 3.31's without the PP, PP picks up 3.55's

 

[Spartan]

I would agree with you. However, we did some research and the actual sticker on the differential indicates 3.31s. Here's a picture of mine, premium EB... Non PP. My window sticker does not show them as an option.

If you look at the sticker closely you can see 3L31 or check this thread for details on the meaning of it: http://www.mustang6g.com/forums/showthread.php?t=20815&page=4&highlight=differential

Seems odd they offer the 3.31 in the EB Auto as an upgrade but don't offer the 3.31 in the GT auto as an upgrade. Wonder why?

 

[slythetove]

Seems odd they offer the 3.31 in the EB Auto as an upgrade but don't offer the 3.31 in the GT auto as an upgrade. Wonder why?

The EB PP gear is lower than the GT PP gear - basically they shift down all gear upgrades. 3.73 becomes 3.55 (PP) and 3.55 option becomes 3.31.

I'm going to go out on a limb and say when you buy a GT auto and you think "I would like more rear gear" - 3.55 makes it more fun than 3.31. Not really a limb I guess since I wouldn't have purchased a 3.31 upgrade but did purchase the 3.55.

The 3.31 from a 3.15 just wouldn't be worth it to me. The 3.55 is awesome on the GT auto though.

EB:
Manual 6 speed
base 3.31
PP 3.55

Automatic trans:
base 3.15
optional 3.31
PP 3.55

GT:
Manual 6 speed
base 3.31
optional 3.55
PP 3.73

Automatic trans:
base 3.15
optional 3.55

 

[Spartan]

The EB PP gear is lower than the GT PP gear - basically they shift down all gear upgrades. 3.73 becomes 3.55 (PP) and 3.55 option becomes 3.31.

I'm going to go out on a limb and say when you buy a GT auto and you think "I would like more rear gear" - 3.55 makes it more fun than 3.31. Not really a limb I guess since I wouldn't have purchased a 3.31 upgrade but did purchase the 3.55.

The 3.31 from a 3.15 just wouldn't be worth it to me. The 3.55 is awesome on the GT auto though.

EB:
Manual 6 speed
base 3.31
PP 3.55

Automatic trans:
base 3.15
optional 3.31
PP 3.55

GT:
Manual 6 speed
base 3.31
optional 3.55
PP 3.73

Automatic trans:
base 3.15
optional 3.55

Did you drive a 3.15? Havent had a chance to drive both in the Auto yet.

Also, I actually would think that the base Auto GT would be a 3.31 then options to go to 3.55 or 3.73 (PP). Kinda same pattern as the EB...3.15 to 3.31 to 3.55

 

[slythetove]

Did you drive a 3.15? Havent had a chance to drive both in the Auto yet.

Also, I actually would think that the base Auto GT would be a 3.31 then options to go to 3.55 or 3.73 (PP). Kinda same pattern as the EB...3.15 to 3.31 to 3.55

Yes, I drove the 3.15 - it's fine, but I felt the 3.55 made the car snappier and a little more fun for me. I usually buy stick and would have done the PP but the traffic here is atrocious now and I would hate it during those times. I really like the auto 3.55 combo.

 

[Spartan]

Nice. How's your MPG with the 3.55s?

 

[1320']

3.73 would be a terrible gear for the auto...3.31 cars would run it down with ease.

The gearing in the 6R80 is really pretty aggressive and doesn't need or want a ton of gear.

 

[Spartan]

3.73 would be a terrible gear for the auto...3.31 cars would run it down with ease.

The gearing in the 6R80 is really pretty aggressive and doesn't need or want a ton of gear.

So you're saying 1320 to stick with the 3.15s in the auto because you think the 3.55s are just too much for it?

 

[slythetove]

Nice. How's your MPG with the 3.55s?

18 - 23 probably - but this is more a product of me than 3.15 vs 3.55

If you go 75+ on the highway (speed limit 75) you won't see 27mpg regardless of gear

If you have short trips around home and stoplights you will be under 20

I'm amazed at the numbers some folks say they get with their GT, but all I can imagine is they are cruising at 60 mph for long stretches.

 

[slythetove]

So you're saying 1320 to stick with the 3.15s in the auto because you think the 3.55s are just too much for it?

Stock - GT Auto with 3.55 has been putting up the fastest 1/4 mile times consistently.

http://www.mustang6g.com/forums/showthread.php?t=16739

 

[Spartan]

Stock - GT Auto with 3.55 has been putting up the fastest 1/4 mile times consistently.

http://www.mustang6g.com/forums/showthread.php?t=16739

I don't ever plan to track it or anything...mainly DD and some spirited fun...pretty much 50/50 split of driving. Just trying to figure really if those 3.55s really make the car feel different and/or worth it or are needed.

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