Necessary, always install new flywheel/driveplate retaining bolts on replacement. On manual transmission models, the clutch assembly should be removed. In automatic transmission models, remove the transmission and torque converter. Stop the flywheel/driveplate from turning by locking the ring gear teeth with a similar arrangement. Otherwise, use a strap to bolt between the flywheel/driveplate and the cylinder block/crankcase. Slacken off and undo all securing screws, then remove flywheel/driveplate while noting its locating dowel; (take care - it is very heavy). Discard bolts after loosening them as they must be replaced every time they are used again. If deeply scratched or cracked or damaged otherwise on the surface where it mates with the clutch plate, replace this flywheel unless it can still be ground flat again.. Such matter is beyond your capability hence consult any BMW dealer or engine reconditioning specialist in this case. Replace ring gear if badly worn orhas missing teeth . Let a BMW dealer or engine reconditioning specialist perform this task for great results. All manual transmission models have dual-mass flywheels installed in them.Followed by manufacturer there aren't published procedures of checking anything about it but turn inner mass one full turn counter clockwise then mark its position relative to outer mass , reverse rotate it clockwise by hand and measure travel distance moved at outer edge. In general when more than 1-3/16 inch (30mm) of travel movement occurs or less than 19/32-inch (15mm), ask whether new one is needed from any dealer or maybe some expert in transmissions.Clean both mating surfaces of crankshaft and flywheel/ drive-plate as well as clear all traces of locking compound from crankshaft threaded holes.The installation of the flay-wheel/drive-plate on crankshaft includes engaging with locating dowel plus fitting new retaining bolts.Note: use a little bit of locking compound if the new bolts are not pre-coated before installing. Again, lock the flywheel/driveplate exactly as in removal then tighten all screws according to the specified torque setting but in a diagonal sequence. Finally, fit either the automatic transmission or clutch assembly hosing it together with torque converter.