Transmission gs4 equipped with c725 dry dual clutch transmission, fault phenomenon: into the R gear brake release start jitter serious, several consecutive serious stuttering led to stalling, D gear start normal, but driving shift impact stutter obvious.
Fault information: odd clutch speed is inconsistent / even clutch speed is inconsistent.
Considering the R start stalling, normal judgment would be that the clutch 2 clearance is too small, and a test drive revealed a noticeable stutter only when shifting 246 even gears. If the gap is getting smaller, then normally as the plates wear out, the gap should be getting bigger and bigger, resulting in a delayed start.
So by this point two things should be considered:
1, whether the hydraulic release bearing for clutch 2 is damaged and the oil pressure changes causing the clutch to bind too quickly;
2, a problem with the valve body, caused by a change in the oil pressure supplied to the release bearing.
Translated with DeepL.com (free version)
In accordance with the simplified way to first change the valve body assembly on the car, the fault remains. Next arrangement to dismantle the gearbox, back to the original valve body.
Disassembly of the clutch found that the plate is badly worn, and here it is concluded that the plate is badly worn, the gap is not the cause of the reverse gear start stalling, the failure point can only be caused by the hydraulic release bearing, release the brake to start the release bearing began to work, resulting in the clutch combining too fast, no half linkage directly stalled.
Replacement of the clutch and hydraulic release bearing, after replacement and before loading the car you need to adjust the clutch 1 clearance, we also call adjusting the clutch 1 position. The state of clutch 2 is determined by precise computerized control of the release bearing oil pressure without intervention.
The transmission needs to be energized before loading and the diagnostic reads the clutch 1 position information in the data stream. A range of 10mm to 11.5mm is usually sufficient. If the data is out of range it can be adjusted by unscrewing the front of the clutch #13 nut. After adjusting the data to do the hydraulic system exhaust option, let the clutch repeated action to read the data again, if there is an error to adjust again.
After the transmission is installed and test drive, found that the front and rear start normally, but there is still a significant impact on the gearshift, but it is no longer the original car so serious stutter.
Do not panic when encountering problems, first look at whether there is a fault message record, access the fault code, and found that it is still the original fault code.
Now it seems that the original car's fault is actually two parts, the clutch release bearing causes the start stalling, while the shift shock is the other side of the problem. Because the sensor that detects the two clutch speed signals is mounted on the inside of the valve body, this sensor is also a common damaged part, so replace the sensor to solve the problem.
