Difference of 2.73 and 3.55 gears
 

Can anyone tell me how much difference there will be in driveability with going to 3.55's from 2.73's in an AOD trans. Stang?

As I am unable to connect with anyone locally who has done it, driving a car for comparison isn't likely.

Thanks for any info!

I can say one thing, you won't like the rain. It will be easier to do burnouts and with a shiftkit, you could snatch some seconds. Believe me, you won't be sorry you did that change. IMO, a gear change is the very first thing to be done on a mustang. A big difference on the a$$ dyno. What size tires are you running?

the difference between the gear ratio's is noticable however not nearly as impressive in a AOD as opposed to a 5spd. The reason is, the stock AOD sucks, the line pressure is low, and generally not biult for performance that your probably trying to achieve. My buddy did this on his stock 5.0 and eventually decied after not being satisfied, to get the trans upgraded with better bands and clutches and also a shift kit which by the way chirps 1, 2, and 3rd HARD at about 3000rpm. He later went to a 5spd conversion and now has no use for the AOD which has 29K on it. he wants 500 dollars for it including the converter, shifter, and cables.. great deal, and made a drastic change in the car and drivability was awsome. Also he had a manual shift kid installed too. let me know.

I thought the autos already had 3.27s, or was that just an option?

It was back in 85, i believe.

www.mustanggt.org

plenty of info there on the years.

Ok, I went from a 3.08 geared 5 spd to a 3.73 geared 5 spd then added a carb and then went automatic. The milage is 21-22 but I have been able to coax 24-25 if I'm highway cruising and watching the vacuum guage half the time.

3.55's are nice and cute but you wont dominate all until you go to at least 4.11's for an AOD. I thought the 3.73's were way too mild and went 4.56's. They're the perfect gear (well, maybe 4.30's are the perfect gear) and put me at 3k rpms at 80 and I can bark tires on dry cold pavement.

A shift kit is an absolute must. I've played with transgo kits and theyre crap. You should get an "a" servo for $150 to improve trans life with those higher gears and a lentech strip terminator valve body. That will give you constant line pressure and torque multiplication in 3rd gear as well.

Have fun!

Pete

Its a AOD? Get 4.10's

410

Thanks for the responses. In response to "Ieatcamaros", the tire size is 215/60-16, close to oem size.

Don't really need to go to 4.10's personally.

Like I said before, you will find the 3.73's just a tad bit too mild and you will wish you went 4.10's. The 16 inch tires and .67 OD of the AOD allows for a lot of space for improvement.

Go here

http://www.4x4cyberstore.com/website/rpmchart.html

select AOD, punch in your tire specs and see for yourself. You wanna be doing 2400-2500 in OD at cruising speed. That gives you power through all gears.

Switch to t-5 and see how much extra gear our AOD's let us have. We can go up 2 extra steps and get to the same rpm as a t5

like i said earlier, the stock AOD sucks, however with the experience my friend had, he put in 3.73s and he wasn't impresed at all, with an AOD you'll be alot happier with the 4.10s. if you worried about RPM and mileage don't be.. there won't be a huge difference between the two.

With a 4.10 gear and your AOD, you would be turning 2122 rpm at 60 mph. With that size tire you have. With a 3.73 gear, the rpm would be 1929. That is only 193 rpm difference at 60 mph. You will feel much better about your decision if you put 4.10's in. I run 4.10's with my 5 speed and love them. Either way, definitely do not put the 3.55's in it. If I had an AOD car, I would probably run 4.30's. But that is just me.

Like 88fivepointoh said, don't worry about the difference in the mpg between the 3.73's and 4.10's. You won't notice it anyway unless you do a lot of highway driving.

4.56's BABY!!! The 4.56 is to the AOD what the 4.11's are to t5's

...and I highway drive for hours at a time. Has all kinds of interesting new predicaments like the oil heating up and pressure dropping but the engine can handle it and I get 18 mpg with all my other mods. Funny thing is , the car has this quiet spot right around 3k rpms. Darnit!

The stock AOD sucks until you 3k stall it and add a shift kit. Then it turns mean.

Everything he just said...

FOUR-TENS, 4.10s, do it NOW. I run 4.30s, I love them, I went on a long trip so I turned down the fuel to about 35psi and saw 27mpg. Now this is in a 2800lb car, but it can be done. But I am with crazypete, put some gear in it dude.