1990 Speedometer gear swap from 3.54 to my 4.11 ratio truck! - Dodge Diesel - Diesel Truck Resource Forums

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1990 Speedometer gear swap from 3.54 to my 4.11 ratio truck!

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Old 11-27-2011, 05:18 AM
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1990 Speedometer gear swap from 3.54 to my 4.11 ratio truck!

Hey. I have a question what needs an answer quickly because my speedo shows incorrect numbers. I installed Michelin XML 325/85 R16 war tires yesterday and my speedo reads too low now. Of course it does.

I'm just wondering what is the difference between the 3.54 and 4.11 gear ratio speedos? Is it the thing what converts the analog reading to electrical pulses in transfer case tail? is it?

Because I just swapped my transfer case to remanufactured one and I had to take the "converter" off from my old one and put it to new one and I was wondering will my speedo read correctly(I didn't know was it from 3.54 or 4.11 truck). There is just one spiral type gear to the speedo output in transfer case tailshaft. Is it the same in all of these trucks?

So I think my speedo will read correctly if I can get somewhere speedo stuff from 3.54 truck right? Can you guys help me with this? I don't want to buy 300 usd Truespeed boxes if I can do it this way.
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Old 11-27-2011, 08:04 AM
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original older transfer cases used the stewart warner converters, staggared in/out with interchangeable gears, older speedo shop might have converter gears to compensate tire change, you might try a tire size calculator, or gps to come up with the percentage variable to recalculate correct ratio
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Old 11-27-2011, 08:12 AM
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The difference between 3.54 and 4.11 gears is about 16.5% and the difference between gps and my speedo readings is 20%. So it should be pretty close if I use original 3.54 gears. but where to get them? :O
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Old 11-27-2011, 02:17 PM
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I think I found my solution in here!
http://www.transmissioncenter.org/sp...ar_housing.htm

They even ship internationally. ! Yes!
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Old 11-27-2011, 04:17 PM
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You can get the same part from the dealer. Just give them your tire size, rear gearing and they will give you the right sender unit. If I remember mine on a 90 model was about 50 bucks a few years ago. Probly more now.
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Old 11-28-2011, 08:48 AM
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Sorry, we have no Dodge dealers in here
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Old 11-28-2011, 07:52 PM
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Oops!!
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Old 11-28-2011, 08:58 PM
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those prices are awesome, how much for the money conversion to get here, some will be interested in knowing, i love your country
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Old 02-02-2012, 09:16 AM
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Originally Posted by sooty View Post
those prices are awesome, how much for the money conversion to get here, some will be interested in knowing, i love your country
Hey. Nice to know someone likes our county from there as well!

The price including shippings was the same in euros than it is in dollars on the site. About 60euros. If the custom would have been more interested of the speedo box, then the taxes would have been raising the price about 26% more.
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