Dreams featuring cars often symbolize your journey in life, with the driver representing control or direction. In your dream, your sister is driving, which might suggest that you feel she has influence or control over certain aspects of your life.

The presence of the river could indicate emotions or the flow of your life’s experiences, while the wolf is often a symbol of instinct, aggression, or a threat. The wolf sniffing around the river may represent a situation or emotion that feels predatory or threatening. When it charges at you, it could symbolize feelings of being overwhelmed by a problem or fear in waking life that you feel is closing in on you.

Your sister's struggle to drive away from the wolf might reflect a sense of urgency or a need to escape from these threats. Consider what in your life currently feels threatening or aggressive—this dream could be urging you to confront those feelings or situations rather than avoid them.

Overall, this dream may be highlighting the importance of facing your fears and possibly reassessing who is in control of your journey. It may be beneficial to have a conversation with your sister about any concerns you have, as it may bring clarity and support.