My transmission doesnt shift into 4th gear until I drive it the same exact distance on the freeway. I know people had said it might be the relay but I am suspicious that it is either the seals in the transmission or the solinoid itself as opposed to the relay. Does anyone here know how to decearn the little differences in what happens to help me figure out what I should do. I already swapped the relays for another car and things didnt change. THanks...Jeffrey

Jeff,
I had the same problem as you described just a month ago. Thanks to the responses I got from this board I was able to correct the problem. I was given three remedies 1) resolder the overdrive relay 2) power flush the trans fluid and 3) check the wiring of the overdrive solenoid. I did all three, but I finally got overdrive again just yesterday when I replaced my overdrive solenoid. BTW, I also have a 1989 780 turbo.

"My transmission doesnt shift into 4th gear until I drive it the same exact distance on the freeway."

This comment doesnt make much sense, please explain a different way so we ca give you proper advice, what is the same exact distance etc etc.