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Old 03-04-2013, 06:14 PM   #1
Keckdl
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Speedo off, help

Is there a way to retard or advance a mechanical speedometer? My gears in the transfer case (drive/driven gear) are correct for my tire to transmission but it is off approximately 18-22 % roughly.
If there is a way to adjust the speedo or not I appreciate the input.

Thanks,
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Old 03-04-2013, 06:59 PM   #2
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Re: Speedo off, help

Yes you can by swapping out either your drive gear, driven gear or both. Your cable should go into your transfer case. There is a site around here but can't find it yet. I'll post back if I find it......
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Old 03-04-2013, 07:03 PM   #3
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Re: Speedo off, help

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Originally Posted by Ski-me View Post
Yes you can by swapping out either your drive gear, driven gear or both. Your cable should go into your transfer case. There is a site around here but can't find it yet. I'll post back if I find it......
I have done the trans gear calc and it said the setup I have is correct for th700/np208 and 4.10 gears with 33" tires but it is still off.

This is why I ask if you can adj the speedo.

Thanks for the reply
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Old 03-04-2013, 07:01 PM   #4
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Re: Speedo off, help

Here is one website:

http://www.performanceautomatic.com/...ter-gears.html

You'll need to first determine what you have (number of teeth) by figuring out the colors of both gears.
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Old 03-04-2013, 07:16 PM   #5
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Re: Speedo off, help

You might be able to go in and have the speedo re-calibrated but I would suspect that the speedo gears were still off.....don't know.

You could try swapping the easy gear and see if that helps?!?
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Old 03-04-2013, 08:37 PM   #6
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Re: Speedo off, help

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Originally Posted by Ski-me View Post
You might be able to go in and have the speedo re-calibrated but I would suspect that the speedo gears were still off.....don't know.

You could try swapping the easy gear and see if that helps?!?
What do you adjust when you re-calibrate it?

Thanks
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Old 03-04-2013, 07:17 PM   #7
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Re: Speedo off, help

If you are really bored you could convert it to electronic.....but that's a whole other subject! I did it and now my speedo is spot on with 35's.
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Old 03-04-2013, 08:36 PM   #8
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Re: Speedo off, help

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Originally Posted by Ski-me View Post
If you are really bored you could convert it to electronic.....but that's a whole other subject! I did it and now my speedo is spot on with 35's.
Truthfully I would love to make the conversion to electric. That would simplify things greatly! Right now I want to fix what I have because it is cheaper.

On a side note; what is involved in the conversion?

Thanks
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Old 03-04-2013, 10:29 PM   #9
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Re: Speedo off, help

Quote:
Originally Posted by Keckdl View Post
Truthfully I would love to make the conversion to electric. That would simplify things greatly! Right now I want to fix what I have because it is cheaper.

On a side note; what is involved in the conversion?

Thanks
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I don't know if you could do it or not. I did mine on an NP241 transfer case.....

http://coloradok5.com/forums/showthread.php?t=296187
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Old 03-04-2013, 07:53 PM   #10
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Re: Speedo off, help

When I first read the title, a very disturbing image popped into my head.....
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Old 03-04-2013, 09:51 PM   #11
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Re: Speedo off, help

Get a ratio adaptor.
http://www.transmissioncenter.net/sp...____va.htm#350
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Old 03-04-2013, 11:05 PM   #12
Keith Seymore
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Re: Speedo off, help

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Originally Posted by geezer#99 View Post
x2.

I like to throw an adapter on there; it "skips directly to the answer" instead of doing all the intermediate mathematical steps.

The last time I did this the adapter I needed was laying on the workbench (no purchase necessary).

K
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