The tachometer sensor may fail; if the tachometer needle jumps around and the transmission has harsh shifts or does not upshift, this sensor should be checked. This sensor is mounted in a cover at the front of the motor.
Average mileage: 149,125 (124,000–188,500)
Drive Trains affected: 2WD, 4WD, 7.3L V8 Diesel, Diesel
9 people reported this problem