So I FINALLY got my 3.73s in my car, which I like very much by the way, now my speedo is waaaay off. So I need to know how I can correct it and where I can get the parts from. Any help is appreciated. Car is a 91 Auto (AOD) 5.0.
need help with speedo gear correction
- Thread starter iwannarace67
- Start date
Michael Yount
Mustang Master
Check out the link for info on the gear that should help....
http://www.geocities.com/mgnedell/notchback/tech/speedo.html
http://www.geocities.com/mgnedell/notchback/tech/speedo.html
cjman15
Banned
go to a auto parts store around here and get a new speedo gear... if i'm not mistaken, it may be the white 23-tooth gear... not sure, look it up... www.cjponyparts.com carrys them i believe...
i still need to get a gear for my T5, 3.73 gear
i still need to get a gear for my T5, 3.73 gear
notchback
Founding Member
not trying to promote my site here...but....
go to http://www.burnouts.stangnet.com
go to the tech page
and there is a link there for good speedo stuff.
aod's can have 2.73's 3.08's or 3.27's and it depends how many gear jumps you made to which speedo gear you need.
my old aod had 3.27's and was a purple gear. and btw...aod's have a different pitch so you will have to replace them (the speedo gears) every couple years.
but check my site..the links are good
and real quick..under ax code in your door panel....
m=2.73 gear
z=3.08
e=3.27(aod only)
when you jump to 4.10's....you need a jeep speedo gear to be correct
go to http://www.burnouts.stangnet.com
go to the tech page
and there is a link there for good speedo stuff.
aod's can have 2.73's 3.08's or 3.27's and it depends how many gear jumps you made to which speedo gear you need.
my old aod had 3.27's and was a purple gear. and btw...aod's have a different pitch so you will have to replace them (the speedo gears) every couple years.
but check my site..the links are good
and real quick..under ax code in your door panel....
m=2.73 gear
z=3.08
e=3.27(aod only)
when you jump to 4.10's....you need a jeep speedo gear to be correct
5.0 Nostalgia
10 Year Member
For an AOD, you need the 23 tooth gear. It is black for the auto's. When I got my AOD GT 3 years ago, it had the stock speedo gear in and was way off. Then I put the orange one in. That is the one that is supposed to be used for those gears. That didn't work either, so I got the black one and it works great.
Michael Yount
Mustang Master
5.0Guy - depends on what gear you had in there before, and if your rear tire diameter has remained constant. It's all simple ratios when it comes to gears and tire diameters. If your tire size remained constant, and you had 2.73's before you switched to 3.73's, the equation is (2.73/3.73) X 1600 = 1170 miles. If you were checking gas mileage, your numbers just took a big hit. 
Check to see if there is a speedometer shop in your area. If there is, ask about the Stewart-Warner speedometer gearbox. I believe it is either a 777 Series Drive Joint Kits and Parts or 666 Series Drive Joint Kits and Parts. It is a small gear box that fits between the speedo pickup gear on the transmission and the speedometer. It has quick change gears that allow you to choose almost any tire size and rear end gear ratio you want. This will allow you to get the accuracy with within 2%-3% or less. The drawback is that it isn't cheap.
TRWXXA
Member
Go to Latemodel Restoration Supply and order the 23-tooth AOD speedo gear. It's black in color, and I think it was specially made for the AOD tranny. The white 23-tooth gear you hear about is a Jeep part, and breaks very easily in the AOD (I'm told the angle of the splines is not quite right for the AOD).
You might want to get two of them since the teeth are thin and may eventually break after the wear down. You'll it's time to replace it when the speedo needle starts to shake at certain speeds.
The 23-tooth gear will get you close, depending on your tire size. With stock tires you'll still be about 6% to 8% off. That's not too bad since it can leave the factory being 4% to 5% off.
You might want to get two of them since the teeth are thin and may eventually break after the wear down. You'll it's time to replace it when the speedo needle starts to shake at certain speeds.
The 23-tooth gear will get you close, depending on your tire size. With stock tires you'll still be about 6% to 8% off. That's not too bad since it can leave the factory being 4% to 5% off.
