How do you lube speedo cable on "86 F-250, with a 6 cyl. engine,I imagine that's what's wrong, it squeeks like crazy, or should it just be replaced with a new one, and how do you get to the back of the inst. cluster? thanks, Larry

Assuming that you have the old mechanical type speedometer, You have to reach under and unscrew the cable housing from the speedometer housing. The pull out the cable and check for kinks. Buy a tube of the graphite libricant (thin black compound) and lube the cable and then insert it back. Make sure you wear an old work clothes. The lube can be a mess.