Tranny Problems?

Ok what have going on is the my tranny does not want to take off in 3 gear or overdrive but if you put it in first and shift it yourself it just fine just when you try to take off in 3 and overdrive.So I took it to the transsmission shop and the codes I get are PO1698 and PO700 and the say that is a electical problems they send me to a guy that used to work at the jeep dealer. He ran some test and thought that if we put a different tcm in that it would fix it.But he just call me back and said that he put another tcm in the that the PO1698 went away but the PO700 is still there.He was going to put it on the rack and see what he could find out.I just thought I might come on here and see if anyone on here has ever had this kind of problem with these codes.Any advice would help thanks.

You could try checking the MAP sensor and the vacuum line that runs to it. My son's 89 was doing this also. Turned out to be a pin hole in the vacuum line.