I've been having this problem for awhile now, but I've finally gotten to the point where it annoys me too much lol.

92 Dakota 4x4 V6 5 speed, the speedometer bounces around a lot at any speed under 30, and then for some reason over 35 it reads 5mph slow, with some exceptions like at exactly 68mph. So when it says I'm going 40, I'm going 45, says I'm going 70, I'm going 75, etc. Obviously it's reading the miles wrong but I'm not too worried about it as the previous owner actually disconnected the speedo cable for an unknown amount of time (probably because of the bouncing).

Was curious if anyone has had this issue and knows a fix? I've already replaced the speedometer cable, so I guess my next bet would be either the gauge itself or the sensor? If so, where exactly is the sensor on these things?

Here is the link to a video of it.

 

If your speedo is cable driven, there is no sensor for it. Might check the gears for the speedometer drive in the trans. They do wear out.....

 

Assuming it is cable driven, I would suspect the cable. Sometimes you could pull the cluster out, and then pull the cable out of the housing, and lube it. But a new cable is not that expensive. https://www.rockauto.com/en/moreinfo...t=1440&jsn=916

 

I did replace this cable already as my "diagnosis" for the speedo not working at all was the cable was broken. Turns out it was just removed lol.

Would it be in the trans or the t case for a 4wd? I'd imagine if it was in the trans for a 4x4 it would read all wonky when in 4 low.

 

If you have a 4x4, yeah, it'll be in the tailshaft of the t-case.