Calling all gearheads...3.31 versus 3.55

glyppus · 06-30-2006

I've got a question for the experts...From reputable source, I understand all the new 07 Mustangs are coming out with a 3.31 gear ratio (V6, GT, Shelby). However, you can special order a 3.55 gear ratio on the GT Manuals only.

Did they do this to boost the gas mileage ratings? And why only offer the optional 3.55 on the GT Manual, and not the Shelby?

Also, am I wrong in understanding that 05 and 06 GT Manuals came standard with the 3.55? Would there be that noticible a difference between a 3.31 and 3.55? (I'm not talking about drag slip times here, but more like that "I'm being pressed back in my seat" feeling)

nghtrnnr · 06-30-2006

Quote:

Originally Posted by glyppus

I've got a question for the experts...From reputable source, I understand all the new 07 Mustangs are coming out with a 3.31 gear ratio (V6, GT, Shelby). However, you can special order a 3.55 gear ratio on the GT Manuals only.

Did they do this to boost the gas mileage ratings? And why only offer the optional 3.55 on the GT Manual, and not the Shelby?

Also, am I wrong in understanding that 05 and 06 GT Manuals came standard with the 3.55? Would there be that noticible a difference between a 3.31 and 3.55? (I'm not talking about drag slip times here, but more like that "I'm being pressed back in my seat" feeling)

honestly...who cares bro...everyone changes em to 3.73 or 4.10 anyway...better question....is there a five year old mustang anywhere with stock gears?

ski · 07-01-2006

Quote:

Originally Posted by glyppus

I've got a question for the experts...From reputable source, I understand all the new 07 Mustangs are coming out with a 3.31 gear ratio (V6, GT, Shelby). However, you can special order a 3.55 gear ratio on the GT Manuals only.

Did they do this to boost the gas mileage ratings? And why only offer the optional 3.55 on the GT Manual, and not the Shelby?

Also, am I wrong in understanding that 05 and 06 GT Manuals came standard with the 3.55? Would there be that noticible a difference between a 3.31 and 3.55? (I'm not talking about drag slip times here, but more like that "I'm being pressed back in my seat" feeling)

I do not have any answers from the horse's mouth, but my guess is that it was done to improve mpg ratings with gas staying at approx. $3 a gallon.
You may notice a slight SOTP difference between 3.31 and 3.55 gearing, but like nghtrnnr says it can be swapped out with a lower gear ratio.

kj_cinci · 07-01-2006

So they changed the stick down to 3.31? That used to be tha auto and the stick with 3.55s... maybe it's a fuel price thing? I'd definately get as high a number as available. Also if you chang em go two steps as most going only one seems to regret it...

glyppus · 07-03-2006

Thanks, changing up the gears to 3.73 something to think about going forward, since they shipped out my car on 6/29.
I'm counting the days till its Christmas in July....

kj_cinci · 07-03-2006

For auto 3.73, stick I would go with 4.10s if that's the kind of driving you're going to do (not much highway, playing through the gears...)

Zenmervolt · 07-03-2006

Quote:

Originally Posted by glyppus

I've got a question for the experts...From reputable source, I understand all the new 07 Mustangs are coming out with a 3.31 gear ratio (V6, GT, Shelby). However, you can special order a 3.55 gear ratio on the GT Manuals only.

Did they do this to boost the gas mileage ratings? And why only offer the optional 3.55 on the GT Manual, and not the Shelby?

Also, am I wrong in understanding that 05 and 06 GT Manuals came standard with the 3.55? Would there be that noticible a difference between a 3.31 and 3.55? (I'm not talking about drag slip times here, but more like that "I'm being pressed back in my seat" feeling)

Are the ratios in the transmission the same?

The Shelby's 6-speed has much shorter ratios in the transmission, which cancel out the taller final drive. It's possible that Ford also made a change to the transmission's ratios to compensate for using 3.31's in the GT manual.

kj_cinci · 07-03-2006

Good point but wouldn't that be a mess with spare parts, mech manuals, etc? But who knows, I'm already quite surpriced if the actually changed the rear end gearing as sugested above...?? If EPA was after them it would be the auto first... the only thing I can think of is fuel cost...?? Or commonality...??

The 6-speed have two overdrives, one on each side of ours... I wish I had a 6 then I'd go with 4.10s hands down... not that I can hook no anyways so why bother really...??

Zenmervolt · 07-03-2006

Quote:

Originally Posted by kj_cinci

Good point but wouldn't that be a mess with spare parts, mech manuals, etc? But who knows, I'm already quite surpriced if the actually changed the rear end gearing as sugested above...?? If EPA was after them it would be the auto first... the only thing I can think of is fuel cost...?? Or commonality...??

The 6-speed have two overdrives, one on each side of ours... I wish I had a 6 then I'd go with 4.10s hands down... not that I can hook no anyways so why bother really...??

It's actually really easy to change the ratios on a manual transmission, No parts other than the gears themselves change. Tremec already makes the T3650 with other ratios.

*EDIT: "Really easy" relative to making other changes to the transmission, and it wouldn't really mess up the spare parts.