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DIAGNOSIS 7A2-135
No. G4: Large Noise During Idling with the Vehicle in Stop State • The transmission is noisy during the idling speed in all ranges. • Causes such as solenoid operating sound or faulty oil pump are considered. • Distinguishing to some extent is possible by stopping the solenoid operation temporarily, checking the correlation for the former case and, changing the line pressure and confirming the correlation with noise. • As a matter of course, noise may be generated around the engine, for instance, other than the AT and should be checked carefully.
Note:
When the noise is generated only at the time of gear shift, it may be the sound of flowing ATF or gear noise. If the sound varies depending on the gear speed to be shifted, it may be the gear noise generated from the planetary gear and its related components. If the sound varies depending on the vehicle speed, it may be the gear noise of the output system, and if varying depending on the engine speed, it may be the gear noise of the input system or faulty torque converter.
In either case, sound may be "noise" depending on the origin and resonance object. When the object generating the sound (resonance object) and the sound source (vibration source) are different, investigation of the cause may be difficult. No. H1: Judder Occurs at the Lock-up ・The vehicle body judders at lock-up. ・Slip due to burning of the lockup piston or insufficient fastening due to dropped working pressure are considered. Trouble diagnosis flow is basically the same as "No. I1: No lock-up".
Note:
When the lock-up piston has burnt, foreign material mixed in the oil cooler is considered. In such a case, inspect the oil cooler circuit for clogging of the oil cooler. No. H2: Large Lock-up Shock No. H3: Lock-up Point is High or Low • Large shock is felt at lock-up. • Lock-up point is excessive high or low. • Out of properties of input sensor or faulty lock-up piston pressure system are considered. • Trouble diagnosis flow is basically the same as "No. I1: No lock-up".
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