Thanks for the helpful responses to my earlier post, I ended up taking it to a shop where they replaced the overdrive relay, but to no avail. (My problem is total lack of overdrive, won't shift into highest gear.) Now they are discussing replacement of the solenoid. Now honestly, I do not know what the solenoid is and/or does, but I have heard that they rarely fail. Is this true? I'd be willing to take a hit in the wallet if it fixed things, but I'd just like to inquire about the odds of it really being the solenoid that has failed. Are there any high-level non-tech techniques to diagnose a problem with the solenoid? Because for example, pressing the switch on the shifter will turn the orange arrow on and off, but it has no effect on the shifting. Many thanks and apologies for my incompetence.