This Preliminary Information communication provides information to the technician that steps to diagnose and repair vehicles that have a vibration in the 30-40 MPH range. Technician will need to inspect for obvious signs of damage to the propeller shaft, dents, scrapes, and under coating. If the propeller shaft is damaged replace the propeller shaft. If propeller shaft inspection does not indicate any concerns, then record Pico readings with the sensor placed inside the vehicle where the vibration is felt the most. Technician should rotate the propeller shaft 180 degrees at the rear flange and re-evaluate.