Thanks to the archives my intermittent overdrive not functioning has been remedied. Overdrive would not would occasionally and problem became worse to the point of not working at all. I've had relay problems with another 240 in the past so that was my initial inclination. In those cases the bad relay would turn the overdrive off light on and overdrive wouldn't work. This time the od off light wouldn't come on and if I clicked the button the light would come on and off but it had no effect on the overdrive.

After a search on the archives I began to suspect the solenoid or wiring.
Upon inspection it turned out to be the wire to the solenoid from the switch. It looked ok but one touch and the insulation crumbled. It must have been intermittently touching metal and shorting out.

After patching up overdrive back to normal.

Just thought I'd post with the hopes it can help someone in the future.

Cheers, Kirk S.