Ok, my dad has a 92 5.0, and his speedo doesn't work. The speedo needle just jumps everywhere when he drives. My first thought was the little speedo gear in the cluster, but I don't know, so what do you guy's think would cause the needle to jump everywhere?

 

check the two plastic gears in the trans. if all the gears are good its probly the cable

 

I'm going with the cable. You can try and lube the cable with some graphite but they're not too expensive and if you're already in there to lube it, it's just as easy to replace

 

OK, so were is this cable at exactly, and if you know about how much do they cost.

 

You have to pull the gauge pod out and it's attached to the back of the speedo on one end and at the tranny on the other. I'm not sure what they cost but i'd check with Randy to see what his cost then see if any of the 5.0 resto shops sell them.

 

I really would pull the gear in the trans out first and inspect, although its probly is the cable checking the gear only takes one bolt about ten minutes to do, and if it is the gear you saved time by not pulling the cluster out, have seen the doughnut gear missing a few teeth and when spinning the needle rises till it gets to the point where the teeth are missing causing the cable to stop spinning and the needle drops till the teeth catch up,(causing the bounce) if the gear that comes out has no signs of abnormal wear then the round gear should be fine, if its a little chewed up use a light and spin the drive shaft to inspect the other gear. always check the simple stuff first, work smart not hard!

 

does the odometer work?

if not then leave it b