What did I do to my car?
 

I drove my 83 300SD up on ramps to troubleshoot a problem with speedometer working only intermittently. I removed the speedo sensor then put it back in. Now the car will not turn over. It is an automatic trans. All fuses in the fuse box look okay and there is electrical power. All things (that I know of) function except the car does not even try to turn over. I would think that there is a detector that is tripped when the trans is in park but I cannot find it. What did I do to my car?

Make sure the selector is in P or N. If the bushing is worn/loose it can not get all the way where it needs to be for it to allow the starter to work. Maybe run it through the gear range and back up to P to reset it.

Ramps do have their limitations!!!

If starting in P doesn't work, also try N. Could be the neutral safety switch (and/or shifter bushings as another post suggested).

Read the archives on how you can bypass the neutral starter switch and circuit. Box on the inner fender I believe.
There is a good chance you disturbed the wiring or neutral starter cutout switch probably accidentally. If not that I would forgo any lotto ticket purchases this week.