jbs07stang

Hope this helps some of you to decide between 4.10 or 3.73 in an automatic GT. I had an 07 Gt automatic with 3.73 gears. I liked the gear but wanted a little more at the time. I had never ridden in an auto with 4.10's. I traded the 07 for an 08 convertible GT automatic. I went with 4.10 gears in the 08. If I had it to do over again after having both gears, I would put 3.73's in the 08. The reason is interstate driving. I love the 4.10's from 0-65 better than the 3.73. From 70 up I like the 3.73's better. If you never drive interstate and never go over 70 mph go 4.10 in my opinion. If you do a lot of 70+ mph, I would do 3.73. This is just my personal opinion. At 80 mph I am turning 3000 rpm. With 3.73 around 2700 rpm at 80. I can swap my own gears and cost is not an issue due to that fact. I am not dissatisfied with the 4.10's enough to change back to 3.73. It doesn't bother me too bad to turn 3000 rpm at 80 mph. I would just prefer the 3.73 overall a little more. From 3.73 to 4.10 is not as noticeable as 3.31 to 3.73 in my opinion. The 4.10 does give a little more pull from a dead stop than 3.73. To me the extra pull is not enough to justify the added rpm at 80 mph. Again, if you rarely go over 70 mph get 4.10's in my opinion. If you drive 70+ a lot, I would go 3.73. Please. no bashing me for the comments above. I am only trying to help people torn between gears like I was. I have now experienced both in an automatic. I hope this info can help someone decide. In the meantime I will enjoy my 4.10's and stay around 75 on the interstate. Whichever gear you decide on, it makes a big difference on these cars.

nicksfoursix

Thank you jbs07stang for your comments.
I myself have an '05 GT Auto currently turning a 3.31 gear set. I am tossed between the 3.73s and the 4.10s. The angel on one shoulder says 3.73s while the mischevious devil on my other shoulder screams 4.10s!!!! in my ear.
Even though the bulk (98%) of my driving in under 75 mph. I'm still leaning towards the 3.73s.
I feel this gear set gives me more driving flexibility under normal driving conditions and leaves a "bigger window" open for future modifications. Conversely, I envy the acceleration factor found with 4.10s.
I really don't think there is a "wrong" gear. With the right amount research, anyone can
arrive at "their" proper gear size.
And as far as bashing your comments...I simply wish their were more honest, straight-forward posts like yours. If someone wants to bash your comments then they might as well bash mine as well.

SirKnightTG

Good post. This has re-assured me that getting 3.73 for my auto is the right thing. I want more gear since 3.31 is a dog at times, but I do 70 and some times higher a lot.

Have you run into any gear whine problems? Seems to be a common thing on here.

mb2

thanks man im fixing to buy some gears and find myself on the interstate quiet a bit so 3.73 may be for me

jbs07stang

No gear whine on either of the cars I have had. The key to no whine is pinion depth and the proper preload on the bearings. If set correctly you should not have any gear whine.

MustangRacing4.6ltr

why cant ford racing just make 3:90's lol

stealth_GT

you're right about the 4.10s being too much on the freeway at 80.. it bugs me more then I let on. Getting fatter tires to drop it down to 3.90s or installing 3.73s next year...

NaplesFL11GT

Very good post on the selection of these two gears. I am going to with the 373 gear eventually because I plan to get a blower come next spring. Thanks for the great write up!

jdog78

How was your gas mileage going from 3:31 to the 3:73. I want to do this for my car

jbs07stang

3.73 will increase mileage around town. It is not much of a drop on interstate either. Maybe 1 to 2 mpg on interstate.