Gear unit and drive train for a vehicle

A gear unit (3) for a powertrain (2) of an at least partially electrically driven vehicle (1), comprising a stepped planetary gearset (4), a first gear shifting element (5) and a second gear shifting element (6), wherein the stepped planetary gearset (4) has a first sun gear (7a), a second sun gear (7b), a first ring gear (8) and a plurality of stepped planet gears (10) rotatably mounted on a first planet carrier (9), wherein the first ring gear (8) is configured to be drivingly connectable to an electric machine (11), wherein the first planet carrier (9) is connectable to an output shaft (12) of the gear unit (3) so as to be fixed with respect to rotation relative to it, wherein the first gear shifting element (5) is configured to fix the second sun gear (7b) relative to a housing (13) in a closed state, wherein the second gear shifting element (6) is configured to fix the first sun gear (7a) relative to the housing (13) in a closed state, and wherein one of the two gear shifting elements (5, 6) is in the closed state for driving the output shaft (12) in rotation.