how to find out rear gear ratio - Team Camaro Tech
Troubleshooting Diagnosing problems done here.

 
LinkBack Thread Tools Display Modes
post #1 of 8 (permalink) Old Aug 8th, 00, 06:55 PM Thread Starter
Senior Tech
Rick
 
Join Date: Feb 2000
Location: Denver, Colorado
Posts: 222
Send a message via AIM to 1Fast69chevy
Post

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
1Fast69chevy is offline  
Sponsored Links
Advertisement
 
post #2 of 8 (permalink) Old Aug 8th, 00, 07:18 PM
 
Join Date: Apr 2000
Posts: 246
Post

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.
IgnitionMan is offline  
post #3 of 8 (permalink) Old Aug 8th, 00, 07:26 PM Thread Starter
Senior Tech
Rick
 
Join Date: Feb 2000
Location: Denver, Colorado
Posts: 222
Send a message via AIM to 1Fast69chevy
Post

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.
1Fast69chevy is offline  
 
post #4 of 8 (permalink) Old Aug 9th, 00, 04:20 AM
Senior Tech
 
Join Date: Mar 2000
Posts: 715
Post

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

------------------
68 RS, Ash Gold,pwr windows,Hounds tooth
CA420 is offline  
post #5 of 8 (permalink) Old Aug 9th, 00, 05:47 AM Thread Starter
Senior Tech
Rick
 
Join Date: Feb 2000
Location: Denver, Colorado
Posts: 222
Send a message via AIM to 1Fast69chevy
Post

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
1Fast69chevy is offline  
post #6 of 8 (permalink) Old Aug 9th, 00, 06:27 AM
Senior Tech
Carl
 
Join Date: Apr 1999
Location: La La Land, CA
Posts: 2,707
Post

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.

------------------
Click here to see see my car and hear 5-speeds. http://www.geocities.com/casanoc
CarlC is offline  
post #7 of 8 (permalink) Old Aug 9th, 00, 09:28 AM
Moderator
____
 
DOUG G's Avatar
 
Join Date: Mar 1999
Location: Maryland, USA
Posts: 19,343
Garage
Send a message via MSN to DOUG G
Post

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.

------------------
My68Camaro
Doug G.
68 Camaro
406 ci.
DOUG G is offline  
post #8 of 8 (permalink) Old Aug 9th, 00, 11:07 AM Thread Starter
Senior Tech
Rick
 
Join Date: Feb 2000
Location: Denver, Colorado
Posts: 222
Send a message via AIM to 1Fast69chevy
Post

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.
1Fast69chevy is offline  
Sponsored Links
Advertisement
 
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Team Camaro Tech forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address.
NOTE we receive a lot of registrations with bad email addresses. IF you do not receive your confirmation email you will not be able to post. contact support and we will try and help.
Be sure you enter a valid email address and check your spam folder as well.



Email Address:
OR

Log-in










Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode



Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome