rear gears.
 

i recently found a post on finding what rear gears are on your mustang. this was for 8.8. is says that

3.5 rotations = 3.55
3.75 rotations = 3.73
4 rotations = 4.10

i checked this with my car and with 2 rotations i turned the wheel once. also found the tag on the diff and it says there 2.80's does this sound right? think it should be 3 rotations if its 3.80's

also theres a code on the tag.. cant find it in my mustang book on what the code means. anyone know if its useful?

OK, we'll make this as simple as possible.

1.) Jack up one side of the rear axle. Put the transmission in neutral.

2.) Turn the rear wheel if possible. If you can not, you have a limited slip differential. If you can, then it's an open differential.

3.) If you can turn the wheel, the wheel will turn 2 times what the ratio is for one turn of the drive shaft. I.E., 5.6 turns for a 2.80. Incidentally the 2.80 is the most common.

Rev

ok rev no offense or anything but im not an idiot. i know what im doing. i know how to find if i have a limited slip or open diff. and i know how to find my gear ratio. i was simply stating that fallowing a pattern from a previous post did not make sense for my application.. 2 rotations from my driveshaft makes one tire rotation. if i fallow that pattern then i would have a 2.00 rear gear. witch dosnt exist. but the tag on my diff says i have a 2.80. so if i fallow the pattern then it should have ben about 3 rotations if it were a 2.80. My other question was about the other numbers and letters on the tag from the diff.

im sorry if there was any confution on my question but i felt that you insulted my intelligence. Not everyone here is an amature.

gears
 

the tag is probably rightfor the car.that is the same gears that where in mine before i went to the 9 inch.

Dude, chill out. If you were insulted by rev's answer to your question then I think you ought to re-read everything again. Would you rather have someone speak below your level or above it? Me I take below any day of the week when I don't know someone from Adam.
As for your tag, I don't rember exactly what those signify, but as I recal it was some internal code for the maufacturer and had no real significance as to the gearing.

The important point that Rev made that you may have overlooked was to have one wheel on the ground while trying to determine your ratio. If both wheels are raised, you may not get an accurate result. The point Rev made that I found confusing was the "2 times" part. The ratio simply means the amount of times the driveshaft turns for each turn of the driven rear wheel. For example, 3.55:1 means the driveshaft would turn 3.55 times for every 1 turn of the driven rear wheel. If your driveshaft makes two complete revolutions when the wheel is turned one complete revolution, your gears would be 2.00:1. I doubt that this is the case, so I would recommend trying it again. Mark the shaft and the diff housing near the u-joint with liquid paper to make sure the rotation is counted correctly.

Good luck.

Take care,
-Chris

yeah thats what had me wondering. it was 2 rotations of the driveshaft. thats what i meant when i said it rotated 2 times. but 2.00 gears dont exist on a stock mustang. would it make sense to put those in there if they did exist? I will try and check it again. i used a black marker to mark the driveshaft and the inside of the rim. also about the open or limited slip diff. i did have the other wheel lock. but if im thinking about this correctly. then if i didnt have it locked and it was turning then i would get a higher number of driveshaft rotations that would not match a gear ratior right? but insted mine are lower. im sorry i got mad but iv seen a lot of people get the wrong info and argue becuase someone didnt read the entire question.

Thanks to PKRWUD for correcting my thoughts, and , yes, correctly. With two wheels off the ground, the raised wheels will turn XXX times with a limited slip differerial times XXX turns of the drive shaft.

With a non limited slip and with one wheel on the ground, the wheel off the ground will turn twice (2 times if non limited slip) , as may turns. Really, a no brainer.

Rev

its spelled f-o-l-l-o-w mr non idiot man