98 XJ 4.0 145 K miles.
I'm aware of the dash gauges problem, mine had them before I installed the revised dash harness.
Yesterday I replaced the O ring on the speed sensor in the back of the transfer case because oil was leaking out and now the speedometer stays on Zero. All other gauges work fine. I pulled the sensor back out and the gear was not attached to it. Found it laying in the housing, looks like new. I snapped the gear back in the sensor and put it back in but the speedometer still reads zero. Any Idea what the problem is? Do the sensors self-destruct when you take them out? Is there some special procedure?

 

Did you put it back in the same rotational position? It can be clocked to accommodate different speedo gear sizes. You might have to rotate it back to the correct position.

 

I didn't know I had to note the position. OOps. So I don't know what the correct position is. Now what do I do? I have the 3:07 ratio differentials.

 

The retainer clip only holds it in 4 different rotations. Just try the other 3 :}

 

Thanks! The second position I tried worked.