T-5 Tailshaft Speedo Gear

[Foxbody5.8]

I have had problems with my speedo since i bought the car. Does anyone have any information on the tailshaft gear? I have 3.08 gears, but my speedo reads about 140 at 55mph. I think my tailshaft gear is wrong, i was told stock is yellow, but mine is white. How many teeth should this tailshaft gear have? I have tried an 18 and a 20 tooth gear for the end of the speed sensor, but they dont help. The sensore gear teeth are black and maroon, the black one reads about 100 at 55 and the maroon read about 140 at 55. They forgot the clip on the tailshaft gear when they rebuilt the tranny, so i had to take it apart and put the new clip in, however i didnt speculate that that gear was wrong so i left it. If any one has any info on this subject pleae let me know.... Thank you.

 

[Wicked One]

This is the best I found http://www.crt-performance.com/speedometers.htm

 

[Foxbody5.8]

Nice site but i cant complete it because i dont know what my drive tooth gear is.. Its white, i cant tell till i take it apart....

 

[Wicked One]

White is a 19 tooth. for a cable speedo. Looking for the vss I think its 7 but don't quote me yet.

 

[Wicked One]

Found this also.


An important consideration during the gear swap is finding the right drive/driven speedometer gears per your application. Ford used a seven (7) tooth drive gear in the 1983 to 1989 T-5's, then switched to an eight (8) tooth drive in 1990 (used through 1995). If you have 3.73's with an eight-tooth drive, and the highest driven gear with twenty-three (23) teeth, the speedometer still reads 5% fast. With the limited number of gears available, the combinations are (number in the table is the driven gear tooth number to be used with left hand gear ratio and drive gear column):
Rear end ratio / Speedo drive
Six (6) tooth drive
Seven (7) tooth drive
Eight (8) tooth drive

3.27
16
19
21

3.55
17
20
23

3.73
18
21
n/a

4.10
20
23
n/a

4.30
21
n/a
n/a

Part number
E3ZZ-17285-B
E3ZZ-17285-A
F0ZZ-17285-A

Color
Black
Yellow
Green


Note: The above combinations are based on tires with or very near to stock diameter (225/55-16 is 25.74").



Damn hard to make out. Here is the link.
http://www.ffcobra.com/FAQ/speedo.html

Should help

 

[Foxbody5.8]

My sensor gear isnt white, my drive gear is white, ive tried a black and maroon sensor gear, and they both are way off...

 

[Foxbody5.8]

My drive gear is a white one with 6 teeth, the black sensor gear is a 21 tooth and the maroon sensor gear is 17 tooth, my speedo is a little more accurate with the higher tooth gear (110 @ 55 instead of 140)

 

[64Fatblock]

Speedo failure would be my guess. To be that far off says there is more wrong then the combo of drive/driven gears. I think we talked a little about speedo gears awhile ago. Your car should have a yellow 7 tooth drive gear but you thought someone had done something to the trans before you got it. If you have a white drive gear then you would need a C0DZ-17271-A wine colored driven gear. I doubt the problem is in the gear selection, even if you had a 20% margin of error at 55 the speedo would read 66mph. I think your speedo has checked out, I've had them go bad before.

 

[Foxbody5.8]

Thnx Doug, really interested in the one you have but i dont have any cash as of now.. Looked up that codz number and came up with a black 17 tooth something or other, which im sure is right for my car but didnt they come stock with a yellow 7 tooth tailshaft gear, mine is ony 6 tooth and i cant even find another 6 tooth tailshaft gear anywhere...

 

[64Fatblock]

I already sold the 160 speedo I had. Yes it should have the yellow gear in it, someone must have changed it out.