Well, I am finally having a problem with the overdrive. It has been one reliable part of the car until now. I have the manual and will go through the checks of the electrical setup, but thought someone else here might have had this happen to them and could share the solution.
When I am driving the car on level ground or going down a hill the overdrive dis-engages as if I hit the kick-down switch. It goes back into freewheel mode. You can hear something going on under the floor where the trans is: electrical or mechanical, I'm not sure which, but you can hear snapping, like a spark or something clicking into place, not sure which.
When the car is heading up hill, the unit works pretty much like normal.
Thanks for any advice.