AOD owners with 4.10s

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AOD has 0.68 overdrive gear. At 65 mph with 26" tires you would be looking at roughly 2400 rpm.

To figure it out for yourself iwht other variables the formula is....

(Gear Ratio X MPH) Divided by Tire Diameter. Then multipy that by 336 (it's a constant). That is your RPM at the choosen MPH value. Round the RPM up as their will be slight variation in RPM.

Don't forget that gear ratio in overdrive is your rear gear times the OD gear ratio. In this example it's 4.10 X 0.68 which = 2.79


4.10's and an AOD are a match made in heaven.
 
88mustang_5.0sb said:
How about in a 5spd? Is 5th gear taller in the 5spd than 4th is in the AOD? I have the stock 2.73 gears in my 5spd and am wondering what the best upgrade would be.

Nope. AOD has 2.46/1.46/1.00/.068 gears (1st through 4th respectivly) and hte T5 has 3.35/1.98/1.34/1.00/.067 (1st through 5th respectivly). Now the T5 has a couple small variations in gear ratios over the years. But nothing drastic.

See this thread from the Classic section for more info on tranny ratios.....at the start of the thread there is a bunch of tranny ratio info.
http://forums.stangnet.com/showthread.php?t=492026
 
It's easy to figure out - if you have stock 2.73's and you want to go to 4.10's, your rpm will increase in direct proportion with the ratio of the gears. 4.10/2.73=1.50. A 50% increase in rpm (HUGE difference). So, if now you're turning over 1600 rpm at 60 mph, then with 4.10's you'll be turning over 50% faster - 2400 rpm. You can use the same math to compare 3.73's, 3.55's, etc. Others may tell you their rpm, but as pointed out above, that can vary from car to car with tranny, tire size, etc. This math will work for your car no matter what size tires you have on it or what type tranny - provided of course that your tach and speedo are accurate.
 
MUSTHAVE302 said:
for the AOD, don't forget to take into account a lockup vs. non-lockup converter. the 2400 rpm may be right w/ a lockup converter, but w/ a non-lockup, you may be looking at closer to 2600.

That's right! I forgot about that lock-up/non-lock-up info. :doh:
 
If you're going to rebuild the transmission, use a wide ratio gearset and 3.55's. Then you'll have the same overall first-gear ratio as if you were running 4.10's with the stock tranny and won't take it in the shorts on highway gas mileage and engine wear.