A leak from the top flange differs from a side drain joint or the bottom of the unit.
Never put a hand into the grinding chamber. Keep water away from the electrical connection and tell the provider whether the unit hums, remains silent, leaks while idle, or leaks only during sink or dishwasher discharge.
Keep this boundary: A humming motor does not prove the drain is clear, and a clogged sink does not prove the disposal needs replacement.