My thinking is the transmission related codes were always there, are false error codes somehow caused by the pump issue or new codes indicating a new problem.

My assumption is that you verified, by driving hard and easy, that the replacement pump eliminated the symptoms you were having? And, as I understand the current codes were not there when you checked for codes before?

If that is the case, I suggest the first step is to check fuel pressure as the symptoms are the same as before you changed the fuel pump. I asked about junk in tank because that would be higher probability than the replacement pump doing the same thing, especially since it worked fine for a reasonable amount of time.

The less likely possibility is that the pump performance was a symptom caused by something else not associated with the replacement. That would mean the symptoms went away even though you addressed the wrong cause, IMO that doesn't make sense.

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X5 4.6 2002 Black Sap, Black interior. 2013 X5M Melbourne Red, Bamboo interior
Dallas