Author Topic: Speedometer Gear Reduction Unit  (Read 4363 times)

jg4now

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Speedometer Gear Reduction Unit
« on: March 19, 2008, 04:11:32 AM »
I'm new to this so my apologies if I'm in the wrong spot.

I viewed the gear reduction unit Q&A's and didn't find the info I need so I will ask my question.  I'm restoring a 69 Camaro and I want to make sure I get the correct reduction gear unit.

1.  This car was built with F70x14 tires, M22 Transmission and a 4.10:1 rear gear ratio.
2.  Do the gear boxes have date codes on them?
3.  Does anyone know the correct part No. for the gear box that I need?
4.  What about the speedometer gear?  I am confused about the gear.  Should it be an 8 or 9 tooth gear?

Thanks for any help you can give me on this.

 

acelr8

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Re: Speedometer Gear Reduction Unit
« Reply #1 on: March 20, 2008, 03:31:50 AM »
#6476736 dated by #days and year.Like 102 8. I am not sure of the drive gear.But if you find two  I need 1 also.Jeff

68Zproject

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68Z28

jg4now

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Re: Speedometer Gear Reduction Unit
« Reply #3 on: March 22, 2008, 04:18:24 AM »
Thanks Jeff,

Do you know what the numbers on the gear box (1:.666) designate?  I'm guessing that these numbers refer to the gear ratio of the box.  The few gear boxes I've seen for sale don't have the #6476736 on them.  Is that number the GM number?  Will the #6476736 number be a 1:.666 or 1:.777 or a different one?

jg4now

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Re: Speedometer Gear Reduction Unit
« Reply #4 on: March 22, 2008, 04:36:01 AM »
Thanks for the link 68Zproject.

I'm wondering about the #6476736.  Do you know what the numbers on the gear box (1:.777) designate?  I'm guessing that these numbers refer to the gear ratio of the box.  The few gear boxes I've seen for sale don't have the #6476736 on them.  Is that number the GM number?  Will the #6476736 number be a 1:.666 or 1:.777 or a different one?  So far, the gear boxes I've seen for sale don't have part numbers listed with them.  The just show pictures of the unit and the numbers on them are 666 or similar.  If I new which gear ratio I needed, I may be able to find one using that # if the GM part # isn't listed.  From what I have read on the page you refered me to, I believe I need the 6476736 gear box for my COPO.

Thanks for your help! 

68Zproject

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Re: Speedometer Gear Reduction Unit
« Reply #5 on: March 22, 2008, 04:14:54 PM »
I don't know anything about these.  I just saw a picture in the AIM and asked about what it was.  I saw this thread and put it here.  In time, someone may give you the answer you're looking for.  Sometimes it takes a while here.
68Z28

firstgenaddict

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Re: Speedometer Gear Reduction Unit
« Reply #6 on: March 22, 2008, 05:24:21 PM »
That's the ratio of reduction... 1 turn input = .777 turns output...
James
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copo

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Re: Speedometer Gear Reduction Unit
« Reply #7 on: March 22, 2008, 06:47:26 PM »
Here is picture of the speedo ratio box from a Ebay auction couple of years ago.












jg4now

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Re: Speedometer Gear Reduction Unit
« Reply #8 on: March 23, 2008, 03:38:10 PM »
Thanks Everyone.
It seems that that maybe this piece may be a difficult, (if not impossible) part to find.  The picture posted from COPO is quite different that the boxes I have seen for sale.  This car is so correct that it is most important that I find  one of these. I will continue to check for additional responses and share my story with you as the restoration continues.  This is an awesome car.  It is a 9561 COPO with 21,000 original miles.  It spent a couple of its first years on the drag strip and until I found it has been sitting inside for the remainder of its life.  It is absolutely rust free and it was not all cut up when it was raced.  It has beed certified and well documented by COPO connection.   So far iIt has been educational and fun.