We have a 1992 4runner V6 auto. It will not down shift or stay in overdrive, but it will shift by manually doing it. There is no silpping either. Is there such a thing as a modulator valve? I know with some of the older cars they had one and if it went out the tranny wouldn't shift. Thanx in advance for any help. Later Cajun

 

i have a 92' 4runner 3.0 auto too and from what i have experianced the engine and tranny need to get to operating temperature before it will shift into overdrive. Now if you are in operating temerature and it still won't stay in overdrive or downshift then most likely you need to adjust your throttle linkage. Somebody correct me if im wrong cuz thats all i can think of.