steeda_exhaust

i know.. another gear question.
i have searched this topic to death on here and i see that almost all the posts are for manuals. i have an aod tranny and i see very few posts on rear end gears for them. i drive 300 miles a week on the highway, half stop and go, hence the auto, the other half crusin at 75 or 80. i saw MDValdosta said 4.10s or 4.30s for an auto, but i was hoping i could get some more insight as to where my rpm's would be at 80mph for both sets. now its about 2500, so an educated guess would be about 3k with 4.10s
fuel consumption really doesnt matter. i fill up twice a week now, one more trip to the 93 octane store wont make much difference to me.

help/opinions/education in this matter would be grrrrrrrate

many thanks.

NOS/MAN

82 mph with 4.10s is 3000 rpms......3.73s at 3000 rpms is 90mph..i know because i had both 3.73s are in now..

04mustang

is there a difference in rpms with autos compared to manuals with the same gears?

mdvaldosta

Yes, rpms are different in a 5sp vs an auto. An auto has a numerically lower 1st gear - so you need a higher (numerically) gear ratio in the rear end to make up for this - also the auto's will rev higher I think in top gear compared to an 5th gear in a stick. 4.10's will increase your rpm's by right at 20% over stock 3.27's, and 4.30's will increase your rpm's by roughly 24%. So, if you are at 2500 now at 80mph, with 4.10's you'd be at 3000 and with 4.30's you'd be at 3100 - not much difference.

NOS/MAN

you need to compare the o/d ratios to one another ,,to know on highway speeds,to be the same.the t-45 has a 3.37 first gear 4.10s ,,bite you have to shift right after you take off before you make the corner,,,

steeda_exhaust

nosman... might wanna check that bottle for leaks. :-) i have no clue what you are tryin to say here.

which set do you guys think would be best for my application? i really dont wanna have to do this twice.

Thanks for the help.

NOS/MAN

it means, you will have to shift in to second gear before you make the corner ,,on a std. trans..auto no idea,,,,i make leaks on my bottle................[&:]but you are on your own ...i dont want to steer you wrong..

steeda_exhaust

im not worried about being steered wrong. you guys know youre s**t. and besides the decision i make will be on me. not you guys.

leaky bottle = no road rage

NOS/MAN

YES LOTS OF RODE RAGE DOWM HERE.i just run them off the rode with my trucksometimes i get cut off and cuss alot flip fingers and stuff no gun waiving...sometimes its easier to talk the talk then walk the walk...[&:]i got a std trans what you got again??

steeda_exhaust

auto.

i pi** off people that ride 1inch off my bumper. ill slow down and if they dont backoff i STOP. ill let them go around me... im doin 70+ so im not doggin... and if they get angry and flip me off or what not ill book in front of them again and drive slow as hell. had one guy hanging out the window of his minivan screaming at me on the highway. i just pointed and laughed i dont instigate anything until someone does something stupid. im much more content workin on my tan on the way to work then driving like a ****