Ok you old hands out there. I have a stubborn overdrive problem. My overdrive began to quit on my way back from Oregon last year in the form of working going down hill, then going out of OD going back up. Then for a month, it worked fine. After that, it has not worked since. Here is what I have found so far:
1. Lever in-lever out, works as expected at the low speeds.
2. With lever in, I verified that the cable is pushing the correct lever on the transmission to the end of travel, and it free-wheels with no unexpected noises.
3. When you hit the expected 28 or so mph, you can hear a faint click, I think from the relay on the firewall.
4. Tested that relay, and it works fine.
5. Overdrive solenoid works out of the car, but replaced it with another unit that works out of the car and verified it was seated correctly.
6. Wiring was new only a few years ago and connections are clean and tight.
7. Kickdown switch functions as designed.
8. I grounded the terminal on the OD lockout switch to override the OD governor and still, no activation of overdrive!
Bottom line is: I cannot find the problem and all of the components seem to work just fine. It started as an intermittent failure where overdrive would be working, then not work, then work again. It then worked fine for a about a month, and now has quit altogether.
Help me before I drive her off a cliff. At slow speeds though. Ugh!
Still looks good though.
