The O/D light flashes/ blinks on and off. the trans seems fine is it a warning sign?? it happens when the O/D is on when I press the button to turn it off the light remains on like normal. Thanks....

 

The flashing light means your OD isnt working. Change anything or had any maintence done lately?

 

It dose shift into over drive. I had the trans flushed a few weeks ago and the light was flashing then also. everything seem fine just the light blinks on and off. i don't know??? thanks.

 

If you can actually 100% tell its shifting into overdrive, I dont have a clue. It usually blinks when its not connected anymore. I wish I could help more but I sold and gave away all my 4runner service manuals. Good luck...