Assembly comprising an internal combustion engine

The arrangement has a disk-type intermediate piece (4) connected between a flywheel (2) and a coupling device (1), and transmitting torque between the flywheel and the coupling device. The intermediate piece includes an opening (11) located in a center. A starter generator (5) arranged within a flywheel housing (6) and operatively connectable to a crankshaft of an internal combustion engine. A shaft body (12) is axially movably mounted in the opening of the intermediate piece. The shaft body is connected to the coupling device by a flexible transmission element (13) i.e. flex plate. An independent claim is also included for a method for assembling a drivetrain arrangement for an internal combustion engine.