Speedometer gear

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Dec 27, 2010 | 12:09 PM

Blackwaterforge

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Joined: Feb 2005

Posts: 468

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From: Alabama

Speedometer gear

I need a speedometer drive gear for a 66 F-250.
It has a Borg/Warner 4-speed and 410 rear end.
The choices at the parts store are brown, green and yellow.
Mine appears to be white.
I cannot determine tooth count until I remove it.
I would like to get replacement parts before I disassemble as this is my daily driver.
The speedometer gear is on the drivers side of the transmission if it matters.
Speedometer cable rotates clockwise.
Thank You!

Dec 27, 2010 | 01:26 PM

Flyn66dtmn

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Joined: May 2005

Posts: 581

Likes: 1

From: Montana

first of all how did you determin that it is white with out removing it.? anyway it only takes about five minutes to take a 7/16 wrench and pull it out count the teeth and put it back together. i do believe that the different collars are a relation to the amount of teeth on the speedo gear. prolly get slaughtered for that comment. i have a drawer with about 7 of these different gears as i have changed out so many rear ends in the past and i keep them when i junk out a truck. prolly the only way you'll get the right one is count the teeth, Dutch

Dec 27, 2010 | 01:40 PM

Blackwaterforge

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Joined: Feb 2005

Posts: 468

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From: Alabama

I need the "drive" gear not the driven gear.
I can see the color of the gear through the hole where the driven gear goes.
I can not correctly determine the tooth count.
Thank You!

Dec 27, 2010 | 02:19 PM

patmedic

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Joined: Nov 2006

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From: Divide , Colorado

BlackwaterForge you need to get a hold of ND, I would buy that man a steak dinner (or a dinner of his choice) if I ever met him. A man with that talent and knowledge is amazing.

Dec 27, 2010 | 02:55 PM

66f-100

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Joined: Apr 2008

Posts: 619

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From: Montpelier, VA

Assuming your speedo was accurate to start with, you can use this formula to calculate either the driven or drive gear. You will need to know the diameter of your tire which you should be able to look up on the Internet or you can find that info in the tire section of Summit Racing's catalog.

Speedometer Calibration Program - Method 1

Dec 28, 2010 | 07:09 AM

Flyn66dtmn

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Joined: May 2005

Posts: 581

Likes: 1

From: Montana

sorry Blackwater, misunderstood altogether, i have never taken one of those out. Dutch

Dec 28, 2010 | 07:38 AM

65jim

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Joined: Feb 2010

Posts: 151

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Blackwater forge, If you can give me the trans id (T18 or T98A) and your rear axle ratio, I can give you the teeth count and also the 65 part no for the drive and driven gears from a 65 ford parts book. Should be the same for a 66.