So the only way to get the car moving is to start in gear? And once you start it, the car is already moving forward even before you release the clutch?
If that is the case, there are only a couple different possible causes.
1) The slave cylinder is not engaging far enough. This can be due to the slave leaking off the hydraulic pressure internally, air in the line, not enough fluid (a leak), the master leaking off the pressure internally, or the slave being plain broken.
2) The slave is engaging plenty far, but the pressure plate is not releasing. This can be due to the pressure plate being broken, the clutch disc shredded and jamming up the works, the clutch disc welded itself to the flywheel, the throwout bearing is broken, or a problem with the release fork.
Obviously, if it is anything to do with item 1 it can generally be fixed as is. Anything to do with item 2 and you have to drop the transmission. Basically if it is a hydraulic problem, your golden. If it isn't, your screwed. Basically.
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