pop the rear cover off, as you would for a fluid change. The carrier should have a tone ring on it.

Normal 8.25:



Our 8.25:

 

Ok, I'm sorry but I see you said normal 8.25 and our 8.25. What am I supposed to see? I'm mechanicly inclined but don't see what I should be looking for.

I really appriciate your help though, this is a great forum and I hope to be keeping my Dakota forever!

What is a carrier and tone ring, and where are they located in that image?

Thanks for your help, I really really appriciate it because I need to get this fixed because I don't know how fast I'm going.

 

To answer your question about the 33's. I have a 2.7L 4 cyl tacoma with 285/75R16 approx 33x11.50 and it has no problem getting them rolling. But it won't out run any cops and I can't impress my buddies with an smokey burnouts, but it goes down the road just fine so you will be fine with 33's on your 3.9.

 

Thanks for letting me know on that tamcnally, because my friend has a set of 33's sitting around and wants to sell them to me.

 

In the bottom picture, see what looks like a sprocket behind the ring gear? That drives the sensor.

What the sensor does, is it checks how many tones (teeth) pass by it in a specified time. The more tones it recieves, the faster the vehicle is going. If something happened and a standard 8.25 carrier was put in the axle, it won't have that tone ring. So the sensor won't be picking up any tones to tell the computer the vehicle is moving.

 

Hey, arnt these sensors magnetic? maybe there is some old fashion metal shavings sticking to it, causing it to freak out? have you tried just replacing the sensor again, maybe you got a faulty one. or take out the current one and see if there is anything stuck to the end

 

I would like to believe they are just simple magnetic reed switches....

 

Did you follow the wires from the top of the sensor? I had to replace mine about year ago, and it didn't fix anything right away. I thought I had a bad replacement sensor, but later realized I some of the original wiring was frayed and replaced it and the gauges started working again.

If that doesn't work, just be adventurous - I'm sure the cop will understand

 

had/have close to same problem with gauges (speedo and tach and the rest of MY gauges)

Check the grounds my friend. the CAV C1 connection pin 4 and 5 are the grounds. pin 4 is the logic ground for the I/O processor and 5 is the cluster ground. have to have both to work. they ground to the left and right side of the dash panel by the door. check them.

bad speedo sensor would not cause the tach not to work.



check out this link

http://bionicdodge.com/Download/Spee...d%20Tricks.pdf


LOTS of good info here

KillerKilgore


MISS READ THE ORIGINAL POST
I read TACH and instead of ODOMETER

MY BAD

KillerKilgore