speedometer gears

Engine, transmission, rear-end, driveline, fuel system etc..
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marklein
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speedometer gears

Post by marklein »

Does anyone out there know how many different speedometer drive and driven gears there are for the np435. I would like to know so that I can get my speedometer close. I am using a trans from a 65 slant six truck. It is the small adapter and the short gear. I have made an adapter so I can use a 3 wire speed sensor from a 94 magnum truck. I am using the 94 gauges, so I need the speed sensor. I think I will be able to adjust pinion factor using a scan tool. Thanks.

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MadMC63
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Re: speedometer gears

Post by MadMC63 »

If you all ready know what the pinion looks like there are a multitude of sites that that give the tire size, rear end ratio and what pinion gear you need to correct the speedo. Luckily for you the shorter pinions are usually cheaper.
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marklein
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Re: speedometer gears

Post by marklein »

I found it in the fsm. It appears that the one used in the trans is 5 teeth, unless it came from a very high geared truck or 3/4 ton and up. Anyone know what availability of gears is like? From calculations, I think I'll need a 13 tooth driven gear, anyone have one they can spare? I suspect I will need a ratio adapter too. Will need to get it together to find out.

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chilort
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Re: speedometer gears

Post by chilort »

I don't know if autos and manuals take the same gears or not. Last time I went to a dealer to try to buy a gear the price was astronomical. Luckily, the autos used the same gears for years and in multiple models so I sourced some from the junk yard. I grabbed several different gears when I went hunting. I knew what I needed right then (and it worked -- used to be a calculator on Moparts if I remember correctly but don't know if it is still there) but I went ahead and bought all the ones I pulled trying to find the one I needed to make sure I would have an assortment (but now I don't remember where I put them! :pale ).

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marklein
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Re: speedometer gears

Post by marklein »

Here is the unit.
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