New 1985 owner. 114,000 miles on this one (nice 30 foot red paint job). The last time I drove it, the overdrive unit shifted in and out of overdrive in first gear (at low temps even). It seemed to be related to throttle position, but I'm not sure. I've changed the fluid and filter on the unit, but it looked fine, and there just doesn't seem to be any clear reason for it. And there were no clues in the FRM. Anyone have any ideas on where to look? :confused:

On that year there's a detent cable from the overdrive unit to the throttle body it's probably out of adjustment.
David

Thanks for the suggestion. I'll check it out this weekend. I took it out tonight, and it seems to be more confusing than ever, since at first it basically locked into O/D regardless of gear (1 thru 4), speed, engine temp, or throttle position. After a while it did go back to its random shifting mode (in and out of O/D), so it definitely needs some serious diagnostics.

I will look tomorrow and let you know how to adjust the cable.
David

Thanks to someone on another forum, I checked out the wires going into the connector for the overdrive relay (mounted to the firewall, just behind the fuel pump relay). They were badly frayed and the wire to the overdrive had intermittently picked up 12V from an adjacent wire. The TV cable also may need to be adjusted, but at least the overdrive only works when I want it to. What a relief to find out it wasn't anything serious.