I have some questions...
I am thinking about swapping out the 3.15's in my 13' GT/CS for some 3.73's....any opinion on this as far as feel? I have heard some to to 3.55's and other's to 4.10's....this is a daily driver, but my daily commute is about 5 miles round trip.

What is involved in the process? The local Ford Dealer shot me a price of about $1400 for everything...which seemed very high. The car only has about 3000 miles, so I am thinking gears/bearing kit/ and re-tune/flash from the Ford Dealer.

 

The dealer cannot do anything for you because autos only come with 3.15's. You would need an aftermarket tune to adjust for the gears. The price they gave you is way too high. Also I would keep the stock gears and look to other mods. A good tune and your car with the stock 3.15's and street tires will still shred the tires.

 

^This. Automatics with a quality tune preferably 93 octane , Steeda, Amazon, Vmp etc ; You won't need more than 3.15 gears. The transmission ratios in gears 1 and 2 are extremely low already. Tune it! You'll be more than satisfied.

 

4.10's rock in the 5.0L automatics, even with the steep 1st and 2nd gears in the six speed auto. A good tune, drag radials, and 4.10's and you'll run high 11's in the 1/4 mile and have an entertaining daily driver. Despite what others may tell you, 3.73's or 4.10's are not too much for a 5.0L automatic. DON'T FEAR THE GEAR! Also, $500 to $800 is the normal range for parts & labor for a gear swap.

 

Thanks for all of your input....so the question is:

Can a Ford Dealer Flash my ECU for 3.73's in a 13 automatic?
ie...just have the reflash and no tune?

 

Since its a dd you would want to consider your drive to work. Anything on the highway - higher rpms means worse gas mileage. Anything around town - get through gears quicker so better gas mileage. That's why I decided no on gears bc my entire drive is highway.

 

Check around for a MPH vs. RPM program; my 6M with 3.73 gears runs at about 2200 RPM at 72 (or close) MPH. Not a problem, highway-wise.

 

I really don't care about gas mileage, I've had the car since April and don't even have 3000 miles on it. My main concern is getting the speedometer and odometer correct. That is why I wonder if Ford can do it through a reflash rather than getting a tuner.

 

The dealership can't reflash for that much difference in the speedometer. Get a handheld tuner, use the higher octane tune, and thank us later.

 

dealer dont write tunes and ford doesnt do tunes, the only tune they do is for superchargers and the power pak.thats it, if you do miner changes cai,boss intake etc you need to get a tuner. hope this helps

 

We can debate what gears for the autos until the cows come home and we'll never get anywhere. What there is no debate on is that a tune makes a significant difference in these cars, especially with the autos. If warranty is a concern then get a pair of axle backs of your liking and be done with it.

 

I have a supercharged 2011 auto w/ 3:73s; I always have a smile on my face.
In the grand scheme of things there is not that much difference between 3:31 & 3:55 or 3:55 & 3:73; do what ever floats your boat.

 

Well I have a 2012 auto and I went with 4.10s. There is a big difference between the gears and just having drag radials and a tune. I still get arouse 22mpg while cruising between 65-70 on the highway. I don't believe ford will tune the car for you but I went with Americanmuscle and the bama tune. I can't say anything but good reviews about Bama because I've had my tune adjusted at least 6 or 7 times and only paid the initial price for the tuner.

 

The dealer can change the ecu with pro cal for the 410s or any other gear. They have to install both the gears and the procal. The procal is not aggressive at all, but you will get the correct speedometer reading.It does not adjust shift firmness or shift points. If you go this route and go to a dealer that sells FRPP parts, it will preserve your warranty. You will pay more for all parts through the dealer. If you want a good aggressive tune that will haul ***, do as the others have suggested and buy your gears and tune someplace else.

 

If I ever get to the point where gears are holding me back, then I'll swap them. I can't hook now with 3:15's so no point in them for me at the moment. If it was an all out drag car with well over 1k HP, sure. Just not for my daily driver that sees only highway miles mainly.

 

I'm in the same boat, been debating going to 3.73 or 4.10. Many owners that race their cars often say 4.10s are a blast and not to fear the gear, etc. Some of the fastest 5.0s are running 4.10s and some are running 3.55s, so it all depends on what your mod goals are and how you want to put the power to the pavement. Many say that if you're going FI and putting a super/turbo on soon, that 4.10s are too much and to even stay with the stock 3.15s...I'm not so sure, as I've ran supercharged cars and nitrous cars over 800hp with gears from 4.10 to 4.55, and they simply accelerate like a bat out of hell, but too high a gear isn't streetable. Most say they see 2200+ with the 3.73s at 70ish and 2400+ with the 4.10s, but the weird thing is that many say their avg mpg's go UP when going that steep of gear as it performs better in town and decent on the highway, but YMMV.

Personally, I've swapped gears before and regretted not going far enough (i.e. 3.73 instead of 4.10) so if I do swap I'm going 4.10. Right now I'm running anywhere from 7.77-8.0@83 in the 1/8 on stock tires and 1.98-2.1 60' times, and on Mickey Thompson ET Streets I've ran 7.59-7.80@87 and 1.93 60'...my hurdle to jump at the moment is swapping LCAs/relo brackets/adjustable UCA to get the car out of the hole better, and once I see a decent change in my 60' times (I'm hoping to get in the 1.70s or better) I'll decide whether to change gears and/or add nitrous to get into the 6's in the 1/8 and 11's in the 1/4 mile.

Bottom line...decide what you really want to do with the car, then go and don't look back. If you want a tire burning fury that if it hooks up (if enough rubber is present) it'll rocket out of the hole, go for the 4.10s. If you want a great performer but want to keep the rpm's down on the highway, go 3.73. If you want just a better acceleration but don't plan on tracking the car at all, go 3.55 or 3.73 and you'll be happy. Regardless I'm sure that you'll enjoy the car whichever way you go.

 

I haven't seen any good times with 4.10's. Show me. Otherwise this statement is false. The fastest N/A autos are running 3.31's. Period. Here's one example. Show me someone running in the 10's with 4.10's.
http://www.s197forum.com/forum/showt...t=93180&page=4

 

Some people like low gears, some people like tall gears. It's all personal preference. At the dragstrip there are fast Coyotes with just about every gear ratio. Around town, the lower gears are a freakin' blast to drive. So, the OP just needs to decide if his '13 GT/CS is going to be a track car or a street car, then decide what kind of personality he wants his car to have.

 

+ 1. So many people regret not getting enough gear after a gear swap, but few people ever regret getting too much gear!

My '11 5.0L with the factory 3.73's averaged high 1.9's to the sixty foot mark on drag radials, but now averages low 1.7's (with a best of 1.68) with the swap to 4.56 gears, so I improved a quarter of a second to the sixty foot mark.

Worth noting, I run 29" tall tires on the street and 28" tall drag radials at the track (factory tires are 27.25" tall). So, my 4.56's and tall tires are like 4.30's with the factory height tires. Still a hoot to drive daily, though, and I highly recommend them to anyone who uses their 5.0L primarily on the street with some track days.

 

I haven't seen any good times with 4.10's. Show me. Otherwise this statement is false.

http://www.stangtv.com/features/car-...-block-coyote/

Not N/A But the FASTEST stock long block .This is part of the article.

"JPC left the stock automatic transmission in the Mustang but upgraded it with a Circle D converter with a 3,600 stall. This is backed by the Mustang’s stock suspension system and upgraded 4.10 rearend gears."
"the Mustang ran a 9.61-second quarter mile with a trap speed of 144.24mph. This amazing run granted Bassett’s car the designation of the world’s fastest stock long block Coyote."