|
Author
|
Topic: help -need info for tansmission driven gears
|
tangerine67
¯
Member # 8071
|
posted
 
 
fellas
what have u used to get your speedometer correct when changing gears in the rear end. i have a c-4, and just got 3.73 gears. what driven gear do i need im my tranny ? 21 tooth ? and im reading that..... The drive gear on Ford
rear wheel automatic transmissions is
machined into the output shaft. Changing
the drive gear is impractical since it
requires a new output shaft and transmission
teardown. Most have 7 or 8 teeth.
help
[ September 22, 2010, 06:14 PM: Message edited by: tangerine67 ]
--------------------
Built Ford Tough
Posts: 41 | From: bay area | Registered: Dec 2007
| :
|
|
Captain Obvious
¯
Member # 7842
|
posted
tooth count X gear ratio X tire rev per mile / 1000 (google a calculator to get your tire rev per mile)
example - my transmission has a 7 tooth gear I went with 3.55 and I have 815 tire rev per mile, divide all that by 1000
7 x 3.55 x 815 / 1000 = 20.25 the closest i will get my speedo is with a 20 tooth driven gear
--------------------
It's NOT illegal. It's just frowned upon, like masturbating on an airplane.
Posts: 1976 | Registered: Aug 2007
| :
|
|
tangerine67
¯
Member # 8071
|
posted
quote:
Originally posted by 68stanger:
tooth count X gear ratio X tire rev per mile / 1000 (google a calculator to get your tire rev per mile)
example - my transmission has a 7 tooth gear I went with 3.55 and I have 815 tire rev per mile, divide all that by 1000
7 x 3.55 x 815 / 1000 = 20.25 the closest i will get my speedo is with a 20 tooth driven gear
thats where i need some help- i dont know if my trans has a 7 tooth gear , and i dont know how i get my tire rev per mile ???
--------------------
Built Ford Tough
Posts: 41 | From: bay area | Registered: Dec 2007
| :
|
|
Captain Obvious
¯
Member # 7842
|
posted
quote:
Originally posted by tangerine67:
quote:
Originally posted by 68stanger:
tooth count X gear ratio X tire rev per mile / 1000 (google a calculator to get your tire rev per mile)
example - my transmission has a 7 tooth gear I went with 3.55 and I have 815 tire rev per mile, divide all that by 1000
7 x 3.55 x 815 / 1000 = 20.25 the closest i will get my speedo is with a 20 tooth driven gear
thats where i need some help- i dont know if my trans has a 7 tooth gear , and i dont know how i get my tire rev per mile ???
to figuring out which drive gear you have with out actually looking inside. first find out how fast your car is actually traveling (GPS helps) and whats the difference on your speedo (5-10mph off?) then count the teeth on the driven gear that your currantly using (not the one on the tailshaft) . from there use that formula I posted using either the 8 tooth then the 7 tooth. that should help determine which drive gear your using.
example - im going an actual 50mph but my speedo says 53mph
7t x 3.73 x 815/1000 = 21.28
the mph will be a little off but real close to my actual mph with that 21t gear
8t x 3.73 x 815/1000 = 24.32 (23tooth drive gear is the closest they have for my T5) with that 8 tooth gear my speedometer should be way more off then 53mph (actual 50mph).
its not the most precise way but thats the best you can do without actually checking in there, hope that helps
[ September 24, 2010, 05:19 PM: Message edited by: 68stanger ]
--------------------
It's NOT illegal. It's just frowned upon, like masturbating on an airplane.
Posts: 1976 | Registered: Aug 2007
| :
|
|
|
Email this post to someone!
Printer friendly view of this Ford topic
