[Walt Fricke]

What year car, engine, and transmission do you have, or think you have? It is best, when seeking help, to give those details along with the issue.

The 915 with a mechanical speedometer came on the '72-76 models. On those that boss you point to was threaded externally after the housing was cast. As is typical, when Porsche moved to an electronic speedometer, it didn't change the casting. So your transmission does not have provision for a mechanical speedometer. So either it is a 1977-1983 transmission, or someone changed the nose section of an earlier transmission (which is unlikely).

If you look at the right side of the differential , forward of the axle, you should see a round hole about 2" or so wide, but with a solid bottom. The sender for the electronic transmission goes into that hole, and is held in place by a bent wire which is riveted to the transmission case and rotated into place.

You don't show in your pictures the end of the cable for the mechanical speedometer cable, with its flat end and screw cap. Are those there?

One thing which seems out of place in the photo is what looks like the ball cap end of the throttle linkage, which belongs on the other (left) side of the transmission. Is this just a trial installation?