I have a 1996 Aerostar. On two occasions recently, when I have started up
with the engine cold and backed out of the driveway, I have found that, when
I shifted from reverse to drive, the transmission did not engage
immediately. On the first occasion, there was a lapse in time of about 10
seconds. On the second occasion, I had to shift from drive to drive 2 (it
did engage drive 2) and then back to drive to get it to engage in drive.
The transmission fluid is in the correct range. I have 125,000 miles on the
vehicle and the transmssion was serviced by Ford at 60,000 miles as part of
their regular servicing, not because of any problem.