The Stovebolt Site Forums The Shop Area Driveline T5 Drive / driven gears ?

Hello T5 fans.

I have a T5 from a 93 S10. I am switching out the tail section with one from a 1983 S10 , so I can use my original speedometer.

First I have an assumption based on reading previous posts on the T5 swap. The assumption is that I will need a longer speedometer cable, other than that it's a direct hook up. Am I understanding it correctly?


And some questions.

A 9 tooth drive gear and 18 tooth driven gear came with the housing. Based on my math I will need a 25 tooth driven gear. OR.. 7 tooth drive gear and a 19 tooth driven gear. Is that correct?

for the math I used
Tire (P225/75R15) 28.3 in diameter, 713 rotations per mile.
3.90 rear end

Second question : What is this in the photo. It came on the 1983 housing. From what I have been able to find its some type of reducer? How would it affect the math when determining what drive/driven gear combination.

these are the markings
663A. C9
.7333 AAC


As I understand it, I will not need it If I get the correct drive/driven gear combination.

Thanks for the assistance.

It's a ratio adapter. It will either increase or decrease the speedometer display. If you can pinpoint the manufacturer, you might be able to decipher the numbers to figure out what ratio it is.

I would the .733 is the ratio I have one that shows 1.1 should be able to turn the input side and count the output side to get real close to the ratio.

Otto and Denny
Thanks for the information and terminology.

I did a lot of reading in forums and YouTube watching last night. aparently it's a .7333 ratio to slow down (?) the rotation of the speedometer cable. Thats as I understand it.
Basically a quick correct if you swap rear ends or change tire size. No Idea how to do the math to calculate the ratio a person would need though. Since my transmission is out and I can get to the drive and driven gears, I should not need the adapter. Of course I could be wrong in my understanding.

as for my other question and assumption...

I have a T5 from a 93 S10. I am switching out the tail section with one from a 1983 S10 , so I can use my original speedometer.

First I have an assumption based on reading previous posts on the T5 swap. The assumption is that I will need a longer speedometer cable, other than that, it's a direct hook up.
Am I understanding it correctly?


And a question about drive/driven gears.

A 9 tooth drive gear and 18 tooth driven gear came with the housing.
Based on my math I will need a 25 tooth driven gear if I keep the 9 tooth drive gear. OR.. switch to a 7 tooth drive gear and a 19 tooth driven gear. Is that correct?

for the math I used
Tire (P225/75R15) 28.3 in diameter, 713 rotations per mile.
3.90 rear end
# tooth drive gear.

and this Jegs link
https://www.jegs.com/tech-articles/how-to-choose-the-correct-transmission-speedometer-gears/