Went out today with the wife and tested the transom mount XNT-9-20-T which is hooked up to the Y cable. This time it worked and still read depth at 63mph.
So it looks as if the in hull transducer is faulty or it’s not seated properly or maybe it just can’t shoot through the hull all that well.
I will one day go back into the rear part of the hull and take it out and try to reseal it again just to make sure the transducer wasn’t seal air tight. That’s a good winter project.
Thanks to all that helped with suggestions.