gears
 

what size are the stock rear end gears on an 04 3.9 v6 mustang? and how much gas milage would i loose going to a 3.73 or 4.10 with limited slip? also what size is the rear end? 8.8?

i'd go 4.10's+T-lock(also a tuner) and its 7.5 rearend and you wont lose any gas mileage really unless you play with the pedal alot(lead foot lol)

the stock is 7.5 with a 3.27 ratio. i went with the 4.10's and a posi-trac differential. in the city mpg is about the same. you do go down a little on the highway though since the rpm's will be a little higher. i definately dont feel safe going 116 like i used to, but from 0-60mph, it's a blast. i probably should've gone with the 3.73's since i do a lot of interstate travel, but if you do mostly city traveling, go with the 4.10's. and make sure to save some money for the tuner.

yea i was thinking3.73 cause do travel interstate alot i wish for was like chevy and had 100 diffrent rations like mabey a 3.93 . i was also thinking posi traction instead of locker. Are those gear packages sold on americanmuscle a good deal with the gears tuner and oil?

wow, surprised no one pointed you the the GIANT GEAR THREAD WE HAVE THAT WILL ANSWER ANY QUESTION YOU WOULD EVER HAVE ABOUT MUSTANGS AND GEARS. haha.

3.73 its not THAT much of a noticible difference if u dont lock them up. (HIGHLY recommend u do)

if ur on the highway atleast once a day for 10 minutes at a time. then ull c a difference. but if ur only on it for 5 miles or so then ide say 4 10 and still ide say get a t lock

and btw i THINK i saw some gears on AM a while ago

http://www.americanmuscle.com/99-04-mustang-gears.html

yup here ya go. ide say FRPP....thats just a personal choice though.

top right has the 3.90 u wanted but u might not get much feed back from that on this forum. kinda a rare thing

those 3.90's are for an 8.8 in a GT or Cobra, not the 7.5 in a V6. Don't do gears without a t-lock of some sort. The install price will have no real difference and then you can get rid of the stupid 1 tire fire. also as zig said, check the gear thread, it is a good thing.

thanx if anyone finds somewhere to get 3.90 for a 7.5 rear let me know

They dont make them only 3.73 and 4.10 are gonna be the main choices.

the difference between the gas mileage of 4.10s and 3.73s are 1 mile per tank all together even on the highway...so i would go with 4.10s if i were you. it is a blast to drive.