I understand that the overdrive gear will not kick in until the water temp
reaches 145 degree. My 1986 300 zx, non-turbo, seems to be working right up
to that point. When it does try to go into overdrive, the transmission
starts to slip while going into overdrive, then it goes back to 3rd gear,
back to overdrive, over and over again. sometimes it does it maybe twice or
it may be 6 or 7 times. I did go ahead and had the trany filter and fluid
changed. once it goes in to overdrive and stays there, it will work perfect
every time, until the car cools down to below the 145 degree mark. Does
anybody have a hint on what is going on? Thanks