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Speedo gear?

DEEPWOODS

Contributor
Bronco Guru
Joined
Jul 29, 2007
Messages
1,100
What speedo gear do I need for 35" tires 456 gears and ZF transmission ?
 

Broncobowsher

Total hack
Joined
Jun 4, 2002
Messages
34,835
Viperwolf has a handy Bronco correct speedo gear chart.
Transmission does not matter, only diff gearing and tire size. And the big unknown, which DRIVING tooth count is on the transfer case output shaft. Either 7 or 8 tooth, and that makes a HUGE difference in which driven gear you need on the speedo cable.
 

Viperwolf1

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electron whisperer
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Aug 23, 2007
Messages
24,316
Viperwolf has a handy Bronco correct speedo gear chart.
Transmission does not matter, only diff gearing and tire size. And the big unknown, which DRIVING tooth count is on the transfer case output shaft. Either 7 or 8 tooth, and that makes a HUGE difference in which driven gear you need on the speedo cable.

6 or 7 tooth drive gear.
 

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Broncitis

MEB Founder
Joined
May 18, 2004
Messages
5,267
Has anyone yet determined the rhyme or reason that FoMoCo had between using the 6 or 7 tooth drive gear?

And does anyone know when they went from a steel drive gear to the green plastic?
 

coachbarnes

Bronco Guru
Joined
Aug 3, 2001
Messages
2,705
Loc.
Franktown/Breck, CO
Found this thread on a search, but looks like the right guys are on it to answer my questions.

My speedo was doing the Bronco dance for a while, then just stopped working all together. I don't really care about that, but I do care that my odometer isn't working either. So does this gear go in at the Speedo housing? Or at the Transfer case? Can't really find much on the subject -- starting to troubleshoot to see what I've got to do to fix the problem. Thx
 

thegreatjustino

Contributor
Red Head Grease Monkey
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Jan 23, 2002
Messages
15,624
Loc.
Stockton, CA
The gear is in the transfer case. The non working speedometer and odometer could be the gear, the cable, or the cluster itself.
 

Viperwolf1

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Messages
24,316
Where are these gears available for purchase?
I would be surprised if you couldn't get them from Ford parts. Most Ford model specialty parts places (mustang, cougar, etc) carry them. There are 2 types of gears, those for auto trans and those for manual trans and transfer cases. You want the manual trans type. Its shorter.
 

Broncobowsher

Total hack
Joined
Jun 4, 2002
Messages
34,835
There is also left and right hand spirals. Take your old gear with you and match it. The color will be different, that was how they kept track on the line when they were built.

I just checked "Ford Speedometer Gear" on Amazon and got most of the options on the first page.
 

Seventee

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Sr. Member
Joined
Dec 7, 2012
Messages
997
Loc.
In the sticks of MT
There is also left and right hand spirals. Take your old gear with you and match it.

Yes, be sure to do this. I was accidentally shipped the wrong spiral gear but didn't notice until after I installed it. I then had to change my plastic 205 drive gear because it got trashed in the process.

It's my recollection that the opposite spiral is for a 2wd manual transmission as opposed to the transfer case. They look identical otherwise.
 

Viperwolf1

Contributor
electron whisperer
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Messages
24,316
Jeep and probably scout D20 uses the reverse speedo gears.
 

laserfish

Jr. Member
Joined
Feb 19, 2015
Messages
122
I have 33" tires. Speedo shows about 74 and gps shows 65. Anyone know which color gear would I need to get these closer? I don't expect perfect but anything would help.
Thanks!
 

Viperwolf1

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Aug 23, 2007
Messages
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I have 33" tires. Speedo shows about 74 and gps shows 65. Anyone know which color gear would I need to get these closer? I don't expect perfect but anything would help.
Thanks!
Without knowing which gears you have now the best I can say is 2-3 more teeth on the driven gear.
 

JefeAZ

Bronco Guru
Joined
Aug 23, 2011
Messages
3,038
Loc.
Tucson
So if I dont have the old gear and the new gear teeth have been grinded down, what do I do? ha. 32" tires and VIN says B90 under axle
 

Viperwolf1

Contributor
electron whisperer
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Aug 23, 2007
Messages
24,316
So if I dont have the old gear and the new gear teeth have been grinded down, what do I do? ha. 32" tires and VIN says B90 under axle
First thing I would do is figure out what did the grinding.

B9 is 3.50 ratio.
 
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