I have a 1994 Buick Century. The VSS (Vehicle Speed Sensor) is apparently bad- speedo and odometer erratic, also late shifts. New VSS is $40. at NAPA. What is the procedure to replace it? Anything unusual to watch out for?

2.2 or 3.1?

Aren't they the same anyway Roy? Usually located at the end of the trans tail housing, passenger side???