Swapping rear end gears on a PP?

[analogman]

I have a GT with the PP on order, and am wondering if it would be possible to swap the 3.73 rear end gears for the non-PP 3.15. Most of my driving will be highway. I wanted the PP for the other upgrades it comes with, but would prefer a numerically lower rear end gear ratio for a bit better mileage.

Does anyone have any thoughts?

Thanks!

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[Five Oh Brian]

Any gear ratio for the 8.8" rear end is possible to swap in. I swap gears in just about every Mustang I ever buy. That said, 3.15's with the manual trans will feel like a dog with no low speed torque, and I would encourage you to try out the 3.73's for awhile. Keep in mind that the trans has a very generous overdrive which will help a lot with fuel economy already.

 

[svt93style]

Agree with the 2nd poster. 3:73 on that tall of a tire and a overdrive should be a nice all around gear. I suppose you can swap them to a 3:55 gear as those are listed on the site as well.

 

[Seabee1973]

Switching down to 3.15... there won't be much low speed torque... I understand it's mostly highway but the stop and gos will eat your gas up compared to a higher gear/... it will not make that much a difference cruising the highway...the mpg gain is negligible

 

[blue]

Any gear ratio for the 8.8" rear end is possible to swap in. I swap gears in just about every Mustang I ever buy. That said, 3.15's with the manual trans will feel like a dog with no low speed torque, and I would encourage you to try out the 3.73's for awhile. Keep in mind that the trans has a very generous overdrive which will help a lot with fuel economy already.

Agreed! I drove from Atlanta to Greenville yesterday in my '14 Track Pack GT w/ 3.73's. I drove between 75 and 80 mph and averaged over 23 mpg. I'm sure I could have done a little better had I tried. :ford:

 

[sqidd]

3.73's and a MT-82 blow donkey balls. The gearing is way to short. The 3.31's in my 2012 are too short.

No low end my ass.

 

[stangt911]

I saw a steady 25 mpg on my PP with 3.73 driving 70 to 75 with no AC. Taller gears will give you about one more mpg at that speed. I love the acceleration in 3rd and 4th with this gears. I don't think the gears are worth changing,the mpg difference is too small and you'll need years of highway driving to recuperate the cost of gears. Unless you can have one built already with Pp and 3.15. I seriously doubt that is doable but good luck!

 

[sqidd]

You guys need to spend more time going around corners. The gearing is WAY too short.

I could care less about MPG. But having to grab 5th for anything but a long straightaway drives me nuts.

 

[blue]

I saw a steady 25 mpg on my PP with 3.73 driving 70 to 75 with no AC. Taller gears will give you about one more mpg at that speed. I love the acceleration in 3rd and 4th with this gears. I don't think the gears are worth changing,the mpg difference is too small and you'll need years of highway driving to recuperate the cost of gears. Unless you can have one built already with Pp and 3.15. I seriously doubt that is doable but good luck!

Love 'em. :clap2:

 

[Old 5 Oh]

There're a big difference in transmission gearing between the MT-82 and the AT. First gear in the AT is like 4.1:1, which is huge. (Some old people may remember the first gear in the mid-80s AOD was about 2.8:1, and those came with 2.73 gears. Talk about dogs!)

So the AT does better with 3:15s than the MT would, which is why the MT comes with 3:31s standard. One point that hasn't be discussed a lot is the new tire height. Mustang tires have generally been 25.5 inches high for a long time, since the days of 225/60-15s. All the new tires are a hair over 27 inches. That difference is about 6%, which makes the 3.73s act like 3.50s on the old cars. Not a lot different, but a little.

 

[gzstang]

Every mustang I owned I swapped to 3:73 gears. I'm so glad the PP 15 already has them. Perfect gear for the stang in my opinion.

 

[908ssp]

The 3.73 is too low for first gear it just isn't needed. The easiest way to up the gearing is larger rear tires. The cheapest is changing the rear gear. I'd considered changing the transmission to a T56 magnum.

 

[sqidd]

Every mustang I owned I swapped to 3:73 gears. I'm so glad the PP 15 already has them. Perfect gear for the stang in my opinion.

Not with a MT-82

 

[Seabee1973]

The 3.73 is too low for first gear it just isn't needed. The easiest way to up the gearing is larger rear tires. The cheapest is changing the rear gear. I'd considered changing the transmission to a T56 magnum.

If you think that is low, try an Audi with quattro... you thought the mustang have short gears? Mine is short up to about third gear.... the mustang with 3.73 were awesome for the '14 and it felt much the same as my Audi

 

[Five Oh Brian]

3.73's and a MT-82 blow donkey balls. The gearing is way to short. The 3.31's in my 2012 are too short.

No low end my ass.

I agree that 3.73's and an MT-82 suck. My '11 Brembo GT came from the factory with 3.73's. I thought the gearing was too tall, so I had 4.56's installed. Liked the 4.56's much better! Car launched much better at the drag strip with 4.56's. 3.73's just didn't have enough low end.

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