Could use alittle more info on this. Is it that it doesn't shift into third right away or that it is not going into overdrive. If its not going into third right away it could be two different things. 1 it could be the throttle pressure cable is out of adjustment or there is a bad internal seal in the front clutch assembly which would also give a short delay of engagement in reverse. If it is slow shifting into overdrive it could also be the throttle pressure cable adjustment or a bad seal in the overdrive unit.I would definitely check the throttle pressure cable. This located up by the throttle body and goes down to the top drivers side of the trans. To adjust it there is a push in tab or a pull out lock you can pull out with a small screwdriver up by the throttle body. You push the cable forward to make the trans shift earlier, and pull it back to make it shift later.
