Question:My clutch chatters and feels "jerky"
when I start out from a dead stop. Do I need a new clutch?
Answer:Probably. Chattering and jerking can be caused
by oil contaminated clutch linings (due to an oil leak on the
back of the engine, usually the rear main crankshaft seal), or
by damage to the clutch itself.
For the clutch to engage smoothly, the pressure plate must
come down evenly on the disc. In other words, the surface of
the pressure plate must be parallel to the flywheel otherwise
it won't engage smoothly. If the flywheel is warped (which can
happen as a result of overheating and abuse), it can make the
clutch grab.
On rare occasion, a manufacturing defect in a new or rebuilt
clutch can cause uneven engagement as can improper installation
of the clutch. If someone allows the weight of the transmission
to "hang" on the clutch, it can bend the clutch disk
causing shudder, grabbing or chattering. Damaged splines on the
transmission shaft can cause the clutch disk to hang up and grab.
Another overlooked cause may be loose or broken motor mounts.