After recently installing an auto trans into my Vanagon, I overlooked a
sensor(?) or coil which appears to mount to the top of the trans. I took
pictures before the work started, but neither these nor the Bentley is much
help. The device is cylindrical in shape with a ~6x30mm nut and bolt through
it, and it is attached to another bracket. There are two wires arranged in a
twisted-pair (black/blue). They feed to the front of the van, possibly to
the instrument cluster? Need some help here. Where on the trans does it
mount exactly? What is it called and what is it's function?

TIA, Mike