DongFeng DFA1101GZ5AD6J-907, Service Manual, Page: 13 / 175

General Principles
GL-10
Trouble Analysis
In a vehicle, a part is made up of many components. Some parts like clutch, transmission and rear axle are
interactive functioning. Therefore, in order to find and examine trouble exactly, it is necessary to know the struc-
ture of each part as well as the functional connection between various parts.
To resolve a problem of the vehicle, you must first know the nature of the trouble. To achieve this, you must
get some exact knowledge of the trouble from the customer, including the parts that effect using conditions and
the date of the happening of the trouble.
A trouble may be caused by one or many reasons in most cases. Therefore, to examine and repair requires
the ability of systematic thinking and resolving problems step by step. For example, when the steering wheel turns
unstable, you should first examine the connection mechanism of the pitman arm instead of disassembling the
steering gear rashly, then decide whether the trouble belongs to the steering gear or to the connection mechanism.
When disassembling the part to find the cause of the trouble, proceed systematically and start from easy
problem.
It is a very important way to find out the cause of the trouble according to the manifestation of the trouble
such as abnormal noise, vibration and failure. Listed below are some common trouble signs and their reasons. As
for the detailed trouble analysis, please refer to chapter of each assembly.
1. During starting of the engine (neutral position)
2. After engine started
3. During starting of vehicle
Engine can
not start Listen to the sound of the gear of the
gear of the starter Folo-tru drive
No sound Trouble in starting system
Having sound Engine troubled
Abnormal sound Engage a gear Sound does not stop Clutch cover troubled
Engine troubled
Exhaust system troubled
Sound stops Clutch driven disc troubled
Transmission troubled
Abnormal sound Clutch troubled
Transmission troubled
Propeller shaft troubled
Rear axle troubled
Engine drive belt slipped