At the back of the transmission,next to the bracket supporting the exhost pipe there is a sensor that plugs into the transmission and is held by a single bolt. What is it? I think the o-ring is leaking and want to find out what kind of mess am I getting myself into. Any help appreeciated.

Sensor? If it's above and to the passenger side of the transmission output, it's probably the kickdown solenoid. You'll get a trickle of ATF while the solenoid is out. More like a dribble if you raise the rear rather than front of the car.

Sixto
87 300D

It is actually the wire part that connects as a sort of a "plug-in" that looks like it may be leaking. Can I just pull it out and take a look?

What about the speedometer input? Is it mounted on the tail end of the transmission?

So, where do I look for the other end of the electric wire that's attached to the solenoid? On the battery side, fuse box? Thanks in advance.

Yup. Pointing down and to the driver side at about prop shaft level.

Sixto
87 300D

IIRC that wire goes up through the floor under the front passenger foot area and winds its way to the switch at the end of the throttle pedal travel in the driver foot area. There must be a connector along the way because neither switch nor solenoid will go through the hole in the floor.

Sixto
87 300D

Thank you,sixto,but now I am in a bigger mess: I took the solenoid out to take a closer look and to clean the area around it. Put it back in and did the test drive- transmission would not shift up! Took the solenoid out again and this time I can not even get the bolt to screw deep enough to fasten the coil tight against the body of the transmission.Is the coil to be positioned certain way? Please help.

Try a new thread with a specific subject line like How do I install kickdown solenoid? AFAIK it only goes in one way.

Sixto
87 300D