DROES99STANG

I am going crazy here. I don't know what gears to get. I already posted a forum for gears so please don't be mad at me for posting another one. Now in my last post the majority of the people said get 4.10's instead of 3.73's. But i am thinking those people have manual transmissions. I have an Automatic, and I heard there is a huge difference from automatic and manual when it comes to gears. is that true and why? I tryed to check the RPM Calculations at tchracing.com but it asks for the transmission and I don't know wich one I have there are lots. Do you know what a stock 99 mustang Gt Auto has for a transmission? I did the calculation anyways with the T-45 transmission and with Tire size 255/45/17 and 3.73 gears at 70mph in 4th gear i am turning at 3,371 rpm and with the 4.10's at 3,705 is this a huge difference? and how much would my gas mileage change for wich ever gear you reccomend. i'm not sure that i care about the gas mileage but it depends how dramatically it changes. Can you please tell me what gear I should get for my 99 Mustang Gt Convertible (heavier) Automatic (currently 2.73) and please give me an explination why. Also I will probly be adding a Supercharger but not for a long time!! Thank you very much!!!

AXLE

https://mustangforums.com/m_1692692/tm.htm go there and it may help a bit

DROES99STANG

That is the best thing anyone could have ever done for me. thank you very very very very much. that piece answered all my questions i am definitely going with 4.10's

DROES99STANG

do you have gears? what size? or why not?

Flyingmau5

trust me ... i just got my 4.10s and i cant be any happier!!! =D ur pony will turn into a new beast

Flyingmau5

still havent gunned it yet... right now im doing cycles to warm up the gears..

Albizo66

well it's auto..so i'd say 4.10s or bust (waiting for someoen to chime in that has experience with 4.30s and auto)

DROES99STANG

So does this mean you should put some miles on the car before you get on it with the gears? Because when i get my gears installed that is going to be almost impossible to not stomp it to the floor with the new gears. I love speed I wish I had the money for a Supercharger my car is way too slow for me but i still love her. Can't beat having a mustang!!

MustangMan00

4.10'ssssssssssss the performance shop that isntlaled mine said i they didnt need a break in period, but i drove like prob 50 miles before i stomped on it, or pushed it at all....cuz i have an auto, and u can screw thigns up if u dont get it tuned for the gears

DROES99STANG

So how do you like your 4.10's? I never had a Car with lower gears, everyone tells me there is a huge difference. is it really that big of a difference? Do you wish you would have got 3.73's? or do you have no regrets with the 4.10's? have you drove on the highway? if so is it ridiculous on the highway? And what about gas mileage? was there a big difference? Also everyone says that it feels like you gain a lot of horsepower and torque even though you technically don't gain any hp or torque, did it feel like this to you? Hey Man sorry for all the questions, but I am going to be spending a lot of money on these gears and want to be sure it is what i want. Also what brand were your gears?