Indication of transmission priority class is disclosed for sharing a base station's maximum channel occupancy time (MCOT) for use in autonomous uplink (AUL). Aspects of the disclosure provide for implicitly sharing the MCOT by providing an indication of transmission opportunity (TxOP) length. A serving base station sends an indication of a current TxOP length in control signals to a user equipment (UE). The UE may then infer a set of potential transmission priorities used by the serving base station according to the TxOP length, as TxOP length may relate to the MCOT, which itself may be associated with a particular transmission priority class. The UE may then, conservatively, select the highest transmission priority of the set of potential transmission priorities for autonomously transmitting any uplink data having at least the selected highest transmission priority within configured AUL resource of the current TxOP.