Decided I'd let the Ole girl stretch her legs out the other day when I got on the interstate and pushed it past 85 thay it shows on the dash. After that the speedometer needle would bounce up and down. Took out the cluster and put some grease on the end of the cable and put it back together.. Now the needle just buries itself as soon as the truck starts to take off then just bounces wildly..

I don't know much about this situation can anybody help me?

 

Mine bounces a little too. You can always pull another speedo from a JY truck easily enough; I'm not sure what the fix for this one is, though, aside from time. I'd clean up any grease you can, though.

 

Sounds like the cable is having a problem.
You might be able to pull out the cable and lubricate it. Or it might be time for a new cable.

The speedometer itself is likely fine.

 

One end of the cable usually has a crimped fitting on it. Check to see if the fitting is slipping in the cable. The other end slips into a gear at the transmission some of those gears are nylon. If yours is nylon, make sure that the end of the nylon gear isn't stripped. To test the speedo, Chuck the cable end in a drill and run the drill, the speedo should hold a steady speed. There are businesses that repair/ restore speedos. We have one here in L.A. that I used.

 

Just a note, greasing speedo cables makes them worse and more bouncy and they become stupidly worse in cold weather with grease, same thing with oil just not as bad. What I would do if I were you right now is get some brake clean and graphic lube (it's a powder) and remove both ends of your cable, remove the inside cable and spray both pieces till clean and relube with graphite. Also do NOT grease the speedo head, if you want to lube it use some graphite sparingly.

 

Thanks for the input guys. I'll pull it all apart and go from there.

 

Pulled everything out. The cable is in good condition and I lubed the housing with a dry lithium lube. Now the speedometer is close to accurate, but vibrates fast withing 5mph of your actual speed. I believe the cluster is ok but my drive gear for the cable has some chipped teeth and I think it needs to be replaced. It is the white(yellowish) colored gear. Anyone know how many teeth this is? I put 285/75-16 tires on it, should I change the teeth amount on the gear? Anyone know how many? Thanks

 

Depends on rearend ratio as to which gear. Just count them. IIRC one tooth more drops speedo by 2.5ish mph and one tooth lower will raise it 2.5ish. Plenty on fleabay.

 

Well I would but I'm on vacation..Was going to try and order the parts so they would be waiting on me when I get back.

 

Mine is kinda dingy white and is 20teeth