3.73 speedometer gear

[NoDrama43]

I new there was a cutoff on the gear size. I was thinking it was 3.73. With the 23 tooth gear you will probably be about 2.5 miles and hour off .

[CNTLOSE]

I had a '92 LX AOD car with 4.10 gears. The speedometer gear the shop put in was chewed apart within a few months. I actually ended up putting in a red standard gear which is for standard 3.73's and it was very close to accurate...not sure on tooth count. (Already had it laying in my garage from a previous car.) So I would imagine you could do the same, and since you have 3.73's you should be very close as well.

[FoxChassis]

Red gear (manual trans) is 21T. If that was very close to accurate with 4.10 and an 8T AOD (late '89-'93), the tires must have been huge....enough to bring the final drive ratio way back down.

Drive Gear x Rear Gear x Tire RPM / 1000 = Driven Gear

Drive Gears
6T = Black = E3ZZ-17285-B (T-5 only)
7T = Yellow = E3ZZ-17285-A (T-5 only)
8T = Green = F0ZZ-17285-A (T-5 only)

Driven Gears
16T = Wine = C0DZ-17271-A (T-5) or Blue = D0AZ-17271-A (AOD) (discontinued)
17T = White = C3DZ-17271-C (T-5) or Green = C7SZ-17271-A (AOD)
18T = Yellow = C0DD-17271-B (T-5) or Gray = C7SZ-17271-B (AOD) (discontinued)
19T = Pink = CODZ-17271-B (T-5) or Tan = C7VY-17271-A (AOD)
20T = Black = C1DZ-17271-A (T-5) or Orange = C8SZ-17271-B (AOD)
21T = Red = C4OZ-17271-A (T-5) or Purple = D0OZ-17271-B (AOD)

[NoDrama43]

excellent help by posting the part numbers !! appreciate that for future reference.

[CNTLOSE]

Red gear (manual trans) is 21T. If that was very close to accurate with 4.10 and an 8T AOD (late '89-'93), the tires must have been huge....enough to bring the final drive ratio way back down.

I was running 17x9 Cobra wheels and it was within a few mph...verified by radar.

[FoxChassis]

Factory tires were just under 26" tall.

To be within a few mph with an 8T speedometer drive gear on the output shaft of an AOD, a 4.10 rear gearset, and a 21T speedometer driven gear, the tires would have to have been around 30" tall.