coffee4matt

I have read some great feedback on this website and others but still can't decide. Would love to hear from any members w/ a 5.0 GT, 6 speed AUTO TRANS who have changed to either the 3.73 or 4.10 gear...I believe manual vs auto trans makes difference in pre-vs-post experience.

steven46746

Either will be a big difference, do it!!!

Ltngdrvr

DON'T DO IT!!!

2011+ Mustang automatics will show the best gains from a high stall converter, way more than a gear swap.

If you just have to do the gear swap, remember that a new tune is essential to the proper operation of the transmission.

nordy racer

i swap to 373 gears about 1000 miles into onwership. the car has 24K on it now, and i havent looked back.

mikeyt03

A gear swap is perfect for people who dd their car and don't want a converter. I went with 3.73 and I'm happy with the results.

coffee4matt

Thanks for the feedback Ltngdrvr. A few other questions:

1. Will a high stall converter improve acceleration and low end response off the line primarily just in 1st gear, or does it improve response throughout all of the first 4 transmission gears, the way i understand a higher ratio rear axle would?

2. I have a Bama 93 tune w/ a steeda CAI and it adjusted all my AT shift points. Seems like it now shifts from 1st to 2nd almost immediately. I understand i can use my flash tuner to recalibrate the speedometer to a new 3.73 axle, but no other tune adj's are req'd.

3. I never take my 2011 5.0 convertible to the track, but its a daily driver & I commute 45 miles each way to work, about 75% freeway driving. I put about 15k miles a year on my car so i'm thinking the better gas mileage in a 3.73 vs a 4.10 rear end could really add up over time.

4. Not sure but i dont think Ford even offered a 3.73 axle option w/ an auto trans in 2011, or maybe still. Didnt the Brembo package w/3.73 axle only come in the 6 speed?

Can you say a little more about how a high stall converter would impact drivability in stop and go driving, like when my So Cal freeways back up, or general street driving.

Incidentally, ever since i put new 19"x8.5" wheels and Micheline Pilot Super Sports summer tires on my car a few months ago, i can no longer get the rear wheels to break loose anymore, unlike the old stock all season Pirellis which broke loose on every hard acceleration start.

I'm assuming a 3.73 axle might give me that option back again, of the occasional burnout?

coffee4matt

Thanks!

Out of curiosity, is your 5.0 a stick or auto trans?

Ltngdrvr

Converter:

The high stall converter allows the engine to get up into it's power range right away making for lots better acceleration.

In a car like a Mustang with a lock up converter the high stall is very streetable since the converter locks up, starting in third gear, and the car spends very little time in first and second on the street.

But...

It sounds like you would be LOTS better off not adding a converter OR gears since you put so many miles on the car and do so much highway driving.

You would be lots better off spending the money on some other mods than gears that won't be killing your highway fuel economy.

Actually, the converter fits the bill for you better since it won't change the highway rpm's or mileage at all since it will be locked up at that speed just like the stock converter but will let the car accelerate much harder when taking off.

Tune:

Just resetting the speedometer is not all that is needed from the tune for the gears on an automatic car, all transmission shift points and converter lock up schedule need to be adjusted for the new gears, if you go that way that is.

You would also need a tune adjustment for the high stall converter if you were to go that way.


The converter will cost more to do but will give more acceleration performance, the gears will do some but will cost you some highway MPG's.

topbliss

Correct. My bud has an automatic 5.0 that runs 9.2's and still has the stock 3.15 gear. Don't waste your $$

BadHabit2Break

I swapped to a 3.31, took the lag out between shifts...I love them.

GrabberBlue5.0

Gears are not the answer for the autos. The reason they came with 3.15's is the gearing in the transmissions are very aggressive. Yes 3.15's are the only option on the autos. A converter makes a significant difference. The tune can be fixed so it doesn't shift into 2nd so quickly but and holds 1st longer but it's unlikely Bama can do it as their tunes are ho hum at best. You're not the first to complain of that. You wont get better gas mileage with more gear.

rriddle3

Agreed. The 1st and 2nd auto trans gearing is quite low. As for tuning, I have a Brenspeed on mine and 1-2 and 2-3 will bark the tires and pop your neck without effort.