could have went down vs could have gone down

Some examples from the web:

• I thought I was being careful, but some of the blood must have went down the drain.
• If you had it like that, it would have went down.
• Brayden told him what went down.
• Went down playing basketball 20 minutes ago.
• Small plane went down near Government Canyon Park.
• But something real bad went down inside.
• Except for elective procedures which went down 13 percent.
• Went down for racketeering few years ago.
• So the beheading obviously went down here.
• Went down to Texas for rodeoing.
• I went down... I went down to the hospital, but they wouldn't let me in.
• We went over everything that went down tonight.
• Little irony just went down the wrong way.
• So we went down and had this meeting.
• No, your aura level just went down.
• Sometimes I wish you went down on the Titanic with all your sorority sisters.
• Got caught in a crossfire, went down.
• You were standing right next to me when this went down.
• I worked undercover with Narcotics when all that went down.
• You didn't see what went down.

Some examples from the web:

• Now, there's lots of reasons It could have gone down that way.
• You could have gone down a dark road.
• You know, I could have gone down to the precinct and picked this up.
• You know, it could have gone down the way they said.
• There's no other way that this could have gone down.
• I told TJ it couldn't have gone down like that.
• How could it not have gone down?
• How could the deal have gone down when it's going down right now!
• Cell tower must have gone down.
• Too many bad things have gone down here, man.
• Whatever swelling you had seems to have gone down.
• Since the networks have gone down, I haven't been able to contact them.
• Except he wouldn't have gone down as my father.
• Central locking must have gone down with the computers.
• People far more obsessed than you have gone down that road.
• The devil may have gone down to georgia, Mr. Ford, But he lives in memphis.
• So the diamond had to have gone down with the ship.
• He and some students from school have gone down to the Learning Hall.
• You must have gone down the wrong tunnel.
• 29% of edible fish have gone down by 90%.