I have a 2000 dakota quad cab 4.7 4x4. One day went to appt and came out and transmission started slipping. Made to appt fine. Have replaced all electronics and transmission twice. Still having same issue. Took to trans shop only thing they found was a short in the wires to pressure switch, they repaired the short. They have had it for almost 2 months and still same issue. No codes except for o2 sensor. At a lose as to what to check next. Any ideas really need the help.