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Discussion Starter #1
what is the stock number of teeth on a input shaft or pinion on a 69 camaro 10 bolt 8.2 inch? I have a posi unit with some gears on it, and am wondering what my ratio is. Any other way to find out what kind of gears i have i.e. codes counting teeth etc.

thanks

rick
 

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Count the number of teeth on the ring gear, and the pinion, divide the ring gear number by the pinion number, that's the ratio.

Example: 42 teeth/ring gear, 10 teeth/pinion.

42 divided by 10 is 4.20 Ratio would be 4.20:1

37 divided by 9 would be 3.31 or 3.31:1 ratio.
 

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Discussion Starter #3
I just need to know the number of teeth on a stock pinion for a 69 camaro. Because we have a posi unit with ring atttached, and i want to know what final ratio would be.
 

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There are so many stock gear ratios that you will have to count them if you don't know.

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68 RS, Ash Gold,pwr windows,Hounds tooth
 

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Discussion Starter #5
ALL I NEED TO KNOW IS THE NUMBER OF TEETH ON A STOCK, NON POSI PINION. I have a ring outside the car, and need to know the number to divide total teeth by (#of ring teeth/pinion #of teeth). Does anyone know that? Or are there variable input shaft number of teeth.

Thanks again
Rick
 

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There are many different pinion gears. They can range from 8-12 teeth. It depends on the gear ratio of the set (ring and pinion.) GM installed several ratios in production cars so one cannot make a blanket statement. It would lead you in the wrong direction.

The gears are the same for posi and non-posi.

From a Richmond catalog here's the ratios for 8.2"

Teeth Ring-Pinion Ratio


25 spline pinion
37-12 3.08
37-11 3.36
39-11 3.55
37-9 4.11
41-9 4.56
39-8 4.88
41-8 5.13

27 spline pinion
39-11 3.55
39-10 3.90
37-9 4.11
41-9 4.56

You will need to determine which housing you have. The cover gasket is the key.

If the gasket is 11" oval with 10 holes it's a 25 spline.

If the gasket is 10 5/8" irregular shaped (two scallops at 9 and 3 o'clock) it's a 25 spline.

If the gasket is 11 1/2" irregular shape it is 27 spline.

I bet it's likely a 25 spline.

I-man has an error in his post, 37/9 = 4.11

Gears are matched sets. Mixing and matching pinions and ring gears is a no-no and may lead to problems such as noise and premature wear. That's also why people could not tell you what your gear ratio is. If you have matched sets, but are missing the pinion, you cannot determine what the ratio or pinion should be. If you are lucky the ratio is etched on the ring gear.

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Click here to see see my car and hear 5-speeds. http://www.geocities.com/casanoc
 

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one,
try this, look on the ring gear,should have a stamped number, like 40:10 or whatever,thats your r & P count. then do the math.


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My68Camaro
Doug G.
68 Camaro
406 ci.
 

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Discussion Starter #8
Thank you for all of your responces, i will try to figure out more information. Trying to get rid of my 2.55 gears, so i have to find cheap set.
 
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