The speedo may appear anolog, but the needle is moved electronically. There is a speed sensor mounted on one of the front brake rotors. I forget which one. Make sure the holes in the rotors are cleaned and not all plugged up with mud. That is how the pick up works. If that is not the problem, that vintage had a terrible time with water getting in the speedo unit and shorting everything out in them. The speedo unit is a mini computer and controls the 4wd as well. If the speedo is shorted out, expect to lose your 4x4 sooner or later as well. They don't give those away either. They should, as many of us here have had to replace them. Hope it just a mud pcked rotor, or a broken wire on the pickup.