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View Full Version : {Transmission} AOD Speedo gear re-calibration



Blaze86Vic
04-20-2005, 10:05 AM
I found this chart on the web and thought it would be good for use by all of us that have and are going to change our diff. gear. The driven speedo gear you need to have with respect to the ratio you used in the rear, you might also have to take into account the tire diameter too. I'm not going to bother with that though, because it is likely to end up in-between gears.

AOD with 7 tooth drive gear.
Rear Ration / Tooth Count
2.73---16 teeth or 17 teeth (getting mixed messages on this one)
3.08---18 teeth
3.27---19 teeth
3.55---20 teeth
3.73---21 teeth
4.10---23 teeth

AOD with 8 tooth drive gear.
Rear Ration / Tooth Count
2.73---18 teeth or 19 teeth (getting mixed messages on this one)
3.08---20 teeth
3.27---21 teeth
3.55---23 teeth

The 7 tooth drive gear AOD is the older one so most of the AODs that we have are that, but it would be a good idea to check and see what you have for sure. Now that you know what you need, here is where I found to get it so far. They use frames on their wed site, so I canít link to it right, but this is the page you need. The second one sells the 17 teeth one.

www.steeda.com (http://www.steeda.com/store/-catalog/speedometer.htm)
www.transmissioncenter.net (http://www.transmissioncenter.net/speedometer_calibration_______va.htm)

Thought this was pretty cool to know, so there it is.

85crownHPP
08-10-2005, 11:49 PM
I wonder how I would calculate the correction for my fattie tires... ??

Blaze86Vic
08-10-2005, 11:50 PM
It's not enough... It would mean changing the teeth from 17 to 17.3teeth.

85crownHPP
08-10-2005, 11:56 PM
d'oh!

For the amount of error my tires cause, a gear swap must throw it way off...

Blaze86Vic
08-10-2005, 11:58 PM
You changed gears as well?

85crownHPP
08-11-2005, 11:07 PM
nope mine is stock. I was just imagining that changing rear gears and not the speedo gear must make the speedo read all sorts of crazy.

Blaze86Vic
08-11-2005, 11:20 PM
Oh, hell yeah. With my change from a 3.08 to a 3.55, if I had not changed the speedo gear it would say I was doing 55mph when I would be doing 47mph And it gets worse the higher up.

DuceAnAHalf
08-12-2005, 12:07 AM
http://www.crownvic.net/liquid/speedo_gear.html

mrltd
08-12-2005, 01:39 PM
http://www.angelfire.com/theforce/5ohcpa/cpa5ohtech025.htm


Also has a ton of axle in fo a speedo gear selection info.