speedo gearing
 

counted the teeth on my speedo gears - 20 and 28.

The housing says:

26, 31

32, 38 and


39, 45

Am I correct in assuming that the PO put in a set for a 456? And that the right gears for my 410 should be 26, 31 teeth?

Do gasser gears fit? Local wreckers have no cummins/getrag dodge parts.

Oh, yeah. the speedo has always been about 10% or so high.

As you will find out the Gertag is a different breed of tranny. First of all the output shaft drive gear is held in place by the nut on the back of that shaft. It's the nut holding the drive shaft on the back of the tranny. It is not keyed but simply is held in place by pressure. That being said it dosen't surprise me that you can't find any parts in junk yards.

You probably have the right drive gear or more speciffically the one that was factory installed. Your loco (not mispelled!) Dodge dealer should be able to help with a different drive gear - but I don't think you can get much closer with drive gears. If you want to get closer in your speed you might need to get an adapter from a speed-o shop to correct the variance. To do this you will need to know what your speed is in relation to a know accurate speedometer. When I installed my NV4500HD this is what I did. I had my dad drive at a set speed with his Chev Beretta ( sorry for the cussin :D ) then I logged my speed and gave all this to the speed-o shop they made an adapter that works quite well. I figure I am about 1% off now.

If you need any help with a shop shoot me a PM and I will try to dig out the name of the shop I used - in Portland Or.

Good Luck

Bob

Thanks Bob. As a reformed former rally driver, I have no difficulty callibrating and relating actual speed and distance to those indicated. A stop watch and the 10 km section for speedo callibration will do it. The only challenging part is holding speed at a constant rate like 60 mph or 100 kph. I have done this for several of my vehicles and you get fairly close.

I am hoping that someone out there can tell me if I really do have the gears for a 4:56 rear. (20 on the big one and 28 on the little one) Then I will set out on a hunt for the correct gears. I suppose that the (ptui..) ******* should be able to look this stuff up. I get so depressed when I go there though. [yuk]