Ford 2003 Mustang Workshop Manual page 37

starting point.
Decibel
A unit of measurement, referring to sound pressure level, abbreviated dB.
Drive Engine Run-Up (DERU) Test
The operation of the engine through the normal rpm range with the vehicle standing still, the brakes
applied and the transmission engaged. This test is used for noise and vibration checks.
Driveline Angles
The differences of alignment between the transmission output shaft, the driveshaft, and the rear axle
pinion centerline.
Driveshaft
The shaft that transmits power to the rear axle input shaft (pinion shaft). In a two-piece driveshaft, it is
the rearmost shaft.
Drivetrain
All power transmitting components from the engine to the wheels; includes the clutch or torque
converter, the transmission, the transfer case, the driveshaft, and the front or rear drive axle.
Drivetrain Damper
A weight attached to the engine, the transmission, the transfer case, or the axle. It is tuned by weight
and placement to absorb vibration.
Drone
A low frequency (100-200 Hz) steady sound, like a freezer compressor. Also described as a moan.
Drumming
A cycling, low-frequency (20-100 Hz), rhythmic noise often accompanied by a sensation of pressure on
the ear drums. Also described as a low rumble, boom, or rolling thunder.
Dynamic Balance