2nd Gen Non-Engine/Transmission Speedometer dead

[Tahoeddy]

Hi everyone. My Ram is a 2001 2500 4x4 with the Cummins and 6 speed manual trans.
A few months back my speedometer started acting up. Some days it would not work for a mile or two, then it would come to life. Other days it would be fine.
it's been happening more often and a few days ago it quit altogether. All other gauges and lights are fine and no warning lights are coming on. Can somebody point me in the right direction?
Thanks
Ed in Nevada

 

[KATOOM]

Most likely the problem is the speed sensor in the top of the rear differential. You can take it out and clean off the metallic junk or replace it. If its the speedo itself or related to the cluster then you can test by holding the odometer button down and turning the key ON, holding the button until the cluster runs the test cycle.

 

[Tahoeddy]

Thanks Katoom. I'll try both of those.
I've also read that the wire from the rear end up to the computer is often frayed or broken so I'll try to get a look at that too.
Appreciate your feedback!

 

[fest3er]

Thanks Katoom. I'll try both of those.
I've also read that the wire from the rear end up to the computer is often frayed or broken so I'll try to get a look at that too.
Appreciate your feedback!

Feel each wire carefully. It can be broken inside the quite intact insulation. I think mine is working on breaking again; I should probably replace 2-3 feet of the twisted pair from the sensor forward.

 

[KATOOM]

Thanks Katoom. I'll try both of those.
I've also read that the wire from the rear end up to the computer is often frayed or broken so I'll try to get a look at that too.
Appreciate your feedback!

You're welcome. Hope you get it figured out.

 

[Tahoeddy]

Well I did the test to the cluster. Not sure what I was seeing. Then I cleaned the contacts to the sensor on the diff. Tried to remove it, but was afraid of breaking it so just rotated it several turns and reassembled. Then went for a drive. The speedometer worked! Shut down and restarted five times while doing some chores in town and it worked each time. Not sure what the fix was but I'm pretty sure it was in the sensor or associated plug and wiring, so if it quits again that's what I'll be looking at.
Thanks for the help Neal Murphy!
Ed Ferranto

 

[KATOOM]

Glad you got it working..... Yes, the sensor in the differential can be a bugger to get out as the seal holds it pretty tight in the hole. It will come out with a little perseverance. You may have either cleaned up a bad connection in the plug or the sensor had some metallic dust on it you somehow disturbed. Its just a magnetic sensor running off a tone wheel on the ring gear.