2000 F150 4.2 5-spd 105,000 miles

I have an issue with my speedometer. It has started sticking in the high 70's. In other words, say you speed up to 78, and slow down to 65. Speedo still reads 78 then after you slow down just enough it falls to current speed. Initially this wasn't a big deal, because I try not to go 80 all the time. But now it seems to be occuring more frequently at lower speeds.

Is there a simple fix, lubricate something perhaps, replace VSS? What is the cause and what is the fix? Does this affect the odometer reading any at all?

Any help is greatly appreciated.

Thanks,

C-Shock
'00 F150 SuperCab

It all started with a 1980 F-100 300 6 cylinder...