Shifting into overdrive

I have a 99 laganza and it will not shift into overdrive,i checked and filled the tranny oil and it still acts the same way. Occasionally it will shift but ffor the most part it stayes in 3rd gear while driving. Anyone have this problem or know what it might be?:banghead:

I think there is a temp sensor in these transmission. My car won't shift into onverdrive untill the car warms up. I've had a few cars like this. I don't know where the sensor is exactly nor how much it costs. Worth looking into.



Daklow....