NANO

DRIVETRAIN

411

DRIVETRAIN

TROUBLESHOOTING AND DIAGNOSIS

1. Preliminary inspection

Before performing a road test, preliminary actions can

be taken to diagnose driveshaft noises.

(a) Lift the vehicle on hoist.

(b) Rotate the wheels and listen to”cluck-ing” noise

while rotating wheels.

which needs to check and rectify.

2. Testing driveshaft noises

Following points should be taken into account

while performing a road test in order to diagnose

driveshaft noises :

(a) All the windows of the vehicle should be fully rolled-

up to reduce the disturbances caused by external

noises.

(b) Drive on a smooth road and pay particular

attention to various noises emanating from the

rear portion of the vehicle. Observe the changes

in noise levels through speeds between 10 and

60 kmph.

difficulty in distinguishing between similar noises

resulting from either the drive shaft or from

underbody (for example noise from strut)

(d) Therefore, it is advised that the car be driven on

uneven and bumpy surfaces as well, to observe

the noises which may then be attributable to the

underbody.

(e) Tests for outboard (wheel side) and Inboard (engine

side) joints are different and need to be conducted

separately as given below.

Checking for wheel side joint (OBJ) noise :

NOTE :

This noise will appear closer to the wheel, rather than

the engine.

(i) Shift to the 2nd gear and maintain a steady speed

between 20 and 30 kmph.

(ii) Drive the car to form a figure of “8” as shown in

the figure 3. Identify an audible and persistent

“Cluck” – like noise during either an extreme left

or extreme right turn.

(iii) The “Clucking” noise on a particular turn can be

confirmed by repeating the turn.

Checking for engine side joint (IBJ) noise :

NOTE :

This noise will appear closer to the engine, rather than

the wheel.

(i) Shift to the 4th gear and maintain a steady speed

between 40 and 60 kmph.

(ii) Lower the car speed by gently applying the brakes

while ensuring that the tyres do not screech and

the car does not dive forward.

(iii) Identify an audible” Dug” sounding noise as the

car decelerates. As the car slows down, it can be

observed that the sound would become louder and

occur after longer intervals.