Bouncing Speedo

[benjy_26]

Hello everybody.

 

I recently threw in a full cluster out of a 88 XJ into my '87 MJ and all seems to be well asude from the speedo. 

 

I drove it a few miles last night after buttoning things up and noticed that my speedo needle was bouncing up and down until about 45moh where it stayed steady. I stopped at the gas station to fuel up and afterwards the speedo is not working at all. It's not reading speed or distance traveled. 

 

Y'all think the speedo is dead, or do you think I need a new cable?

[rylee144]

That's what mine did and I had to replace the cable.

[JustEmptyEveryPocket]

Before replacing the cable, I would recommend reseating it at both the cluster and the transfercase. Mine has retreated down the outside sheathing so that it was not making good contact with the back of the gauge cluster. I took it apart at the transfercase and pushed it back towards the cluster while spinning it, then reassembled the transfercase end. Worked fine after that. While you have it apart, consider spraying in some dry lube spray like THIS product to help it spin freely.

[Eagle]

Also, check to be sure that there are no kinks or sharp bends in the route the speedo cable follows from the transfer case to the speedo head. Tight bends can cause jumping.

[JMO413]

You also want to make sure it doesn't touch the exhaust manifold. Just speaking from experience.

[benjy_26]

Thanks for the tips, gents. Anyone know the proper length for a 2wd SWB '87 with an AX4?  Mine is way long and quite likely not original. 

[rylee144]

I couldn't find a short one and had to reroute a long cable to fit. Been working well for about a year. 

[eaglescout526]

9 minutes ago, benjy_26 said:

Thanks for the tips, gents. Anyone know the proper length for a 2wd SWB '87 with an AX4?  Mine is way long and quite likely not original. 

I can’t imagine AMC using eight different cables for two half different vehicles. I can look tonight for the parts and differences in cable lengths between the XJ and MJ but I want to say length of the drive train to the speedo should be the same regardless of the body style. The only differences should be 2WD and 4WD with cruise or without cruise. 

[JMO413]

There's only two choices with our without cruise. They are just long.

[eaglescout526]

That makes sense. I’ve never owned a 4WD Jeep but I can see it. Scratch what I said. JMO is right. With or without cruise is your choices. 

[benjy_26]

Cool deal. Thanks! 

[benjy_26]

Update:

 

My cable failed because it kissed the exhaust.