Re: 1989 ford ranger SHAKE
sounds to me like you need to replace tires. you probably don't notice the shake at a higher speed because your wheels are moving faster than the vibrations will transmit; but anywho. Basically, one of your rear tires probably has broken belting; the way to find this is to raise the rear end, and rotate the tires, running your hand lightly over the tire as it turns. If you feel any kind of area where the tire doesn't seem perfectly round, then spin it faster and watch it--ten to one you'll notice that the tire has some "flat spots", thus, broken belting; by the way, if you drive on broken belts, the tire could blow out on you at anytime.
Billie, my "sparkly" blue 1992 Ranger
SPECS: 2.3 I4; Rebuilt motor at 194,263 miles; straightened driveshaft when engine was rebuilt
FIRST MODS: 2" suspension lift and rear disc brake conversion