Thought I'd share what I found regarding the dreaded Over Drive problems in my 85. After driving for a week I finally decided to take a look at the wiring and found it to be lacking insulation. Fingers crossed and a splice, no luck. Checked for continuity and was getting 12 volts. Changed the relay, still no luck. Up on the ramps she goes. Removing the tranny bracket bolts and the transmission mounts is pretty easy, getting to the solenoid is tricky. After removing it I bench tested and found that the connection on top of the solenoid had deteriorated and there was a lost connection, by putting pressure on top of the connection it activated.
If I had to do it over I would have the replacement part with me, including O rings and double check the 2 bolts after a test drive to make sure they are torqued properly to avoid leaks.Removing the bracket provides a bit more room to get a wrench in there so take a few extra minutes.
Thought I'd share for anybody planning on working thier brick over the holiday weekend.