Decided to do a Transmission oil filter service this weekend. Dropped the pan replaced the filter and filled. When I went to start the engine, the dash doesn't show the car in park, and the car won't start. Moving through the gears has no effect. I pulled the gear position sensor and the continuity seems fine. When I fire up INPA, it shows questions marks and zero for the gear position and it doesn't show any codes.

Is it possible I caused an issue when I dropped the pan? What am I missing, what should I look at next?

2001 X5 4.4 with the ZF5HP24 Tranny

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1995 540i 360K
2003 X5 4.4 130K
1968 Datsun Roadster SR20DET