88 ranger speedo fluctuations

[wyoranch]

My 88 ranger speedo is acting up. It has done it since I bought.it a couple months ago. It stays around the correct speed but isn't steady, moves up.and down lazily several MPH. Also, I have 31" Tires and would like to recalibrate for the tires. How is this accomplished on these trucks? It has a speedo gear in the transfer case and also what appears to be a CSS on the same cable. Seems odd to me

 

[alf030]

As dumb as it sounds, pull the gauge cluster out and make sure the speedo its firmly secured to the cable. I know I pulled my cluster out, and when I put it back it wasn't all the connected and it fluctuated kinda how your describing.

 

[kimcrwbr1]

The senser in the cable could be for the cruise control maybe if you oil the cable end to end it will run smooth sounds like its dinding a little bit. With bigger tires you need a smaller speedo gear in the transfer case pull the cable and find out what color it is maybe get two gears with less teeth the only way to be accurate is with a road test.

 

[kimcrwbr1]

If it is the cruise senser binding and your not using cruise swap out with a solid cable