Symptom Chart: NVH

WARNING: This page is about a different car, the 2018 Ford EcoSport. However, it is still accessible from the selected car via links, so may be relevant.

Symptom Chart

Condition	Possible Sources	Actions
Axle howling or whine	Axle lubricant low	CHECK the lubricant level. FILL the axle to specification. Refer to: Differential Fluid Level Check .
	Axle housing damage	INSPECT and INSTALL a new axle assembly as necessary. Refer to: Axle Assembly . INSPECT and INSTALL new rear differential subframe bushings as necessary. Refer to: Differential Rear Bushing .
	Damaged, worn or incorrect ring and pinion gear contact	INSPECT and INSTALL a new axle assembly as necessary. Refer to: Axle Assembly .
Driveline clunk - loud clunk when shifting from REVERSE to DRIVE	Incorrect axle lubricant level	CHECK the lubricant level. FILL the axle to specification. Refer to: Differential Fluid Level Check .
	Excessive backlash in the axle	CHECK for excessive axle backlash. INSPECT and INSTALL a new axle assembly as necessary. Refer to: Axle Assembly .
Driveline clunk -- occurs as the vehicle starts to move forward following a stop	Loose rear axle mount	CHECK for loose bolts. TIGHTEN to specifications. Refer to: Axle Assembly .
	Extended front to rear tire size differentiation	PERFORM AWD functional test (Pinpoint test A). Refer to: Four-Wheel Drive Systems .
Grinding, popping or chattering - noise from the rear axle when the vehicle is turning	Damaged RDU clutch - discs fused from two-wheel or extended front to rear differentiation	TEST and INSTALL a new active torque coupling clutch as necessary. Refer to: Four-Wheel Drive Systems .
	Damaged or worn differential (differential side gears and pinion gears)	INSPECT and INSTALL a new axle assembly as necessary. Refer to: Axle Assembly .
Grunting -- normally associated with a shudder experienced during acceleration from a complete stop	Loose rear axle mount bolts or suspension fasteners	CHECK for loose bolts. TIGHTEN to specifications. Refer to: Axle Assembly .
Howl - can occur at various speeds and driving conditions. Affected by acceleration and deceleration	Incorrect ring and pinion contact, incorrect bearing preload or gear damage	INSPECT and INSTALL a new axle assembly as necessary. Refer to: Axle Assembly .
Chuckle - heard at coast/ deceleration. Also described as knock	Incorrect ring and pinion contact or damaged teeth on the coast side of the ring and pinion	INSPECT and INSTALL a new axle assembly as necessary. Refer to: Axle Assembly .
Knock - noise occurs at various speeds. Not affected by acceleration or deceleration	Gear tooth damage to the driver side of the ring and pinion	INSPECT and INSTALL a new axle assembly as necessary. Refer to: Axle Assembly .
Scraping noise - a continuous low pitched noise starting at low speed	Worn or damaged pinion bearings	INSPECT and INSTALL a new axle assembly as necessary. Refer to: Axle Assembly .
Driveline shudder - occurs during acceleration from a slow speed or stop	Rear drive axle assembly mispositioned	CHECK the axle mounts and the rear suspension for damage or wear. Repair as necessary. Refer to: Axle Assembly .
	Loose rear axle bolts	CHECK the rear axle for loose bolts. TIGHTEN the bolts as necessary. Refer to: Axle Assembly .
	Driveline angles out of specification	CHECK for correct driveline angles. Refer to: Driveshaft Angle Measurement .