OH, I see it now!

The shifter's arm (not the tranny's) is hitting the case at the rear of the housing. It's like it needs to be raised up or moved over to give it more clearance to the case.

Do you have room to add spacers under the shifter where it attaches to the bracket to raise it up? Or, maybe you could move the shifter base back a little more to give it additional clearance? Perhaps the shifter manufacturer has a different arm for it that is bent to move it over more?

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