Flight Crew Air Transport Pilot (ATP)
Situational Awareness; Distraction; Confusion; Communication Breakdown
ATC Issue All Types; Deviation - Altitude Excursion From Assigned Altitude; Deviation - Track / Heading All Types; Deviation / Discrepancy - Procedural Clearance
Air Traffic Control Separated Traffic; Flight Crew Returned To Clearance
Procedure; ATC Equipment / Nav Facility / Buildings; Human Factors
We are filed to ZZZ from LAX via the CASTA4 Departure. As we contacted Ground to taxi he initially said taxi 24L but then changed his mind and said 'We'll let you go off 25R tonight. So taxi to 25R via Bravo.' No mention was ever made of a different departure procedure. And this is not unusual because the same thing happened to us the night before. So we're still on the CASTA4 which makes a right course change to 311 degrees at MKGEE. That altitude cap is usually 9000 but SoCal thought we were on the GORMAN4 and he gave us an altitude climb to 13000. So when we made the right turn at MKGEE were headed right toward his inbound traffic stream so he screams turn left to 250 and then he starts trying to tell us we're supposed to be in a 250 heading because we're on the GORMAN4. We pulled out the PDC and read it to him. He then told us there was no separation violation but they were looking into it.My question would be how is it that SoCal doesn't know what departure a flight is on. If we've been cleared via the CASTA4 and he thinks we're on the GORMAN4 we've got a major problem.I will avoid this in the future by asking the Tower Controller to verify the departure procedure if there's a runway change.
Pilot doesn't understand how SoCAL [SCT] doesn't know if he is on the GORMAN4 or CASTA4 departure. Aircraft turns northbound and controller vectors it back to a 250 heading.