When the vehicle is cold it will not shift into overdrive. After several minutes however it shifts normally. I changed the transmission filter and fluid. And after some thought and research into the Electronically Controlled transmission I think it might be the Coolant temperature sensor.
Any other ideas or comments?

my vehicle is an automatic 1994 4runner 3.0 L v6 with 4wd.

 

oh yeah the transmission is the A340H.

 

THis is normal for it to not shift until the engine has reached a predetermined temp. unless it is taking a long time to supshift, of if it hunts when warm. In those cases it can be a bad splice joint in the harness that runs along the top front of the engine

 

Hi,
i am new to this one!!!!!!!!!!!!!

 

i have a 94 3.0 with same exact problem, only cold no overdrive, when it warms up i have overdrive if i come to a full stop first ? any clues out there ?

 

Wow this problem is a lot more common then I though as I am experiencing the same thing =(

 

hi i have a 1994 toyota 4 runner 3.0l v6 4x4 4 speed automatic with overdrive, my overdrive light flashes when in overdrive, what can i do to fix it

 

John Dickerson - if it just continues to flash it means the overdrive is not engaged. Did you do any recent work in the engine bay? The connecter may have come loose by unlikely.