23 tooth auto transmission speedo driven gear May 22, 2006, 04:46:05 PM For those of you who have installed 3.73 gears with your stock AOD you know how hard it is to find a speedo driven gear to make your speedo close to accurate. In reality a 24 tooth gear would put it dead on but a 23 tooth gear makes it with in 1-3 mph of being correct. The only problem was that there was no 23 tooth auto trans driven gear avaliable from Ford. You either had to use a 21 tooth gear like I did and accept the 6-7 mph difference between what the speedo said and your actual speed or use a 23 tooth gear for a T-5 which would wear out fast. There is a solution though. I found a 23 tooth AOD driven gear at Mustangs unlimited. I ordered it and it looks just like my 21 tooth gear with 2 more teeth. I installed it and vola my speedo is almost right on. Here's the link if anyone is interested.http://www.mustangsunlimited.com/itemdy01.asp?T1=DFM17271J+01&Category=Drivetrain&subCategory=Speedometer+Gears&CatKey=74-01 Quote Selected
23 tooth auto transmission speedo driven gear Reply #1 – May 22, 2006, 09:20:57 PM Cool... But I have the later AOD with a 7 tooth output. A 21 works fine for me. Quote Selected
23 tooth auto transmission speedo driven gear Reply #2 – May 23, 2006, 12:19:28 AM Don't you also have a Super Coupe AOD? I was going to get a 7 tooth drive gear and pull the tail shaft but I found the 23 tooth driven gear. I figured it's easier to change the driven gear instead of the drive gear. I hope it helps those who are stuck with the py stock AOD for now. Quote Selected
23 tooth auto transmission speedo driven gear Reply #3 – May 23, 2006, 08:16:04 AM Isnt the drive gear on an AOD part of the output shaft? Quote Selected
23 tooth auto transmission speedo driven gear Reply #4 – May 23, 2006, 06:11:14 PM Quote from: slowfoxbirdIsnt the drive gear on an AOD part of the output shaft?Yup it's machined into the mainshaft....Yes I have the Super Coupe AOD... Quote Selected
23 tooth auto transmission speedo driven gear Reply #5 – May 28, 2006, 03:06:12 PM Where is this gear actually Installed at? And does anyone know off the top of their head what tooth gear it is for the 3.55 TC rear? Quote Selected
23 tooth auto transmission speedo driven gear Reply #6 – May 28, 2006, 03:45:19 PM The driven gear is on the VSS sensor which is bolted to the tail shaft of the transmission near the floor pan. It has one bolt and is relativly easy to get at with the car on leval ground, well if you're small like me. All you have to do is unbolt the VSS sensor assembly and you'll see the gear on the end of it. Then just pop the clip off, pull the speedo gear off, put the new one on with the clip, and bolt it back in. Now with a 3.55 gar you might need the 21 tooth purple gear which is avaliable from your local Ford dealer. If not the 23 tooth gear I'm using with 3.73 gears might actually work better with the 3.55 gear as my speedo is still off about 1-3 mph. Quote Selected
23 tooth auto transmission speedo driven gear Reply #7 – May 28, 2006, 08:31:42 PM Yea tried that 23 tooth,laststed 1 month then teeth started coming off.Once i ditched the bird aod and got a stang one all is good with the 21tooth. Quote Selected
23 tooth auto transmission speedo driven gear Reply #8 – May 28, 2006, 11:07:55 PM I used a 23 tooth gear for an AOD and not a 23 tooth manual transmission gear so it should be ok. If you use the 23 tooth manual transmission gear it'll strip easily because it wasn't designed for the AOD. Quote Selected
23 tooth auto transmission speedo driven gear Reply #9 – May 29, 2006, 01:03:09 PM Nope mine was an auto gear,thought it would work and it did for like i said about a month,but if ya wanna try it,be my guest,you'll see,3 months max.It's the reason ford stopped at 21,because any higher and the teeth are too thin and have no lasting strength. Quote Selected
23 tooth auto transmission speedo driven gear Reply #10 – May 29, 2006, 01:39:31 PM if i were you i'd buy a couple more of those gears and keep em handy. the teeth are almost paper thin and tend to get chewed up in the aod's drive gear. a friend and i put 3.73s in his auto mustang and his tranny ate 2 or 3 of them already. Quote Selected
23 tooth auto transmission speedo driven gear Reply #11 – May 29, 2006, 11:50:56 PM Nuts. I thought that because it's for an auto tranney that it would be ok. I should just get a Mustang AOD at some point. Quote Selected
23 tooth auto transmission speedo driven gear Reply #12 – June 17, 2006, 09:14:30 AM What do we have in our cars then...8 tooth drive gears? Quote Selected
23 tooth auto transmission speedo driven gear Reply #13 – June 17, 2006, 09:57:24 AM just joking around but it was alot easier to just buy guages that you can calibrate the speedo at any time.. no more searchin for gears !!! Quote Selected
23 tooth auto transmission speedo driven gear Reply #14 – June 17, 2006, 12:27:55 PM Quote from: 87badbird2613just joking around but it was alot easier to just buy guages that you can calibrate the speedo at any time.. no more searchin for gears !!!And where do you find such items? You still want that stuff nick?...I can do $300. Let me know...tried callin' ya, just got the voicemail, guess you were working or something. Quote Selected