OK. So I just got this truck and the rear end had been swapped out before I bought it. The guy I bought it from said he put 2.70 or 2.76 gears in it. I have yet to spin the wheels and double check. But, judging from me being at 2200RPM at 65mph with my slant six... it sounds right to me.
ANYWAY, When I do check for sure what my ratio is I will need to swap my speedo gear. My odometer at this time is off by .3 miles of travel. Meaning, if I travel 1.3 miles on my GPS my odometer says I have only gone 1 mile.
So, I pulled out my speedometer gear today (I have a NP435 4 speed-granny tranny) and it says on the gear that it has 13 teeth. I also counted 13 teeth... just in case. It is also about 2 1/2" long.
how hard is it to get a new speedo gear?? I have looked on line at a chart saying that if I have 28" tires and a 2.76 rear I need a 26 tooth gear. Does this sound right? 13 to 26 sounds like quite a jump to me. I also read that the pre 66 trans needs a different speedo gear? Is this true also? I just don't know.
I really like this truck and actually want it to tell me how far I am traveling... ALSO because my gas gauge doesn't work I need something to accurately tell me when to get gas. haha
Thanks in advance guys!
OH I have a picture of the gear too I just was too lame to post it here. THANKS!

-Marc

_________________
1965 D100 225 slant 6, NP435 Utiline.

Marc,

First you need to determine what your rearend ratio is by following slantsixdan instructions.

Look here for the correct gear needed, or some other vender for your tire & ratio combination. The quoted price for a new reproduction gear is in the ball park, a used gear may or may not be cheaper.

_________________
67' Dart GT Convertible; the old Chrysler Corp.
82' LeBaron Convertible; the new Chrysler Corp
07' 300 C AWD; Now by Fiat, the old new Chrysler LLC

This is why I think my speedo gear is different:
Instead of a retainer clip I have to remove, then I pull this thing out with an o-ring etc etc.
On my truck, it is like, I undo the speedometer cable, then the threads where the cable screw onto unscrew from the trans housing with my wrench and the speedo gear just sits in there. My gear looks a little different than the ones I see. It does not have this tapered plastic bit on the bottom. ugh...I wish I could figure out how to post a picture... lol
But jumping from 13 teeth to 26 teeth sounds like quite a jump. My truck originally had 3.55 gears I think... I dunno for sure I have to look at the tag on the door again but, if I had a higher gear (in number) that would mean (on the chart) that I would need 37 teeth on my speedo gear not 13...
Just wanna make sure I am getting the right piece.

And I will be checking for my exact rear end ratio this morning. that method is perfect.


-Marc

_________________
1965 D100 225 slant 6, NP435 Utiline.

This is what my speedometer gear looks like.

<a href="http://s990.photobucket.com/albums/af23/garvinoid/Truck%20things/?action=view&current=2010-08-09123654.jpg" target="_blank"><img src="http://i990.photobucket.com/albums/af23/garvinoid/Truck%20things/2010-08-09123654.jpg" border="0" alt="Photobucket"></a>

<a href="http://s990.photobucket.com/albums/af23/garvinoid/Truck%20things/?action=view&current=2010-08-09123625.jpg" target="_blank"><img src="http://i990.photobucket.com/albums/af23/garvinoid/Truck%20things/2010-08-09123625.jpg" border="0" alt="Photobucket"></a>

_________________
1965 D100 225 slant 6, NP435 Utiline.

FYI I measured my rear-end ratio... Flawless method by the way. lol I have 2.76 gears, no Suregrip and my tire size is 235/75/15. I took a tape measure to my tire and it measures 28"... does this mean I have a 28" tire? Or do I have to do math again....

-Marc

_________________
1965 D100 225 slant 6, NP435 Utiline.

The NP435 uses it's own special speedo gears so your can't use the speedo gear charts for "mopar" transmissions. (that is where the 26 tooth count came from)

Try Speedometer World or others offering 4 WD transmission / transfer case parts, they can likely supply the correct gear.
DD