This summer i have had some issues with my overdrive. I have a 1986 pickup with the 22r and the automatic transmission. The overdrive light doesn't flash and it shifts perfectly fine until it should go into overdrive and it just doesn't up shift. I can go 85+ and let off the gas and it won't even think about shifting up into overdrive. Its like it doesn't even exist. The weird thing is that one day I jumped in and headed down the road and it just never shifted into overdrive and thats how its been ever since. Anything i can check or assume may be wrong?

 

There is a wire that runs over the transmission and {I believe} comes down about half way on the drivers side. This controls the overdrive {mine was chewed by rats, gotta love AZ}

 

I just reconnected it with a standard wire connector, I hope that helps