check fluid level. may be low. if not low but dark then due change. if milky or muddied than contaminated.
bring to tranny shop for diagnostic. tech. will advise.
engine temp. gauge flashing? then possible clogged cat.s.
...mean, do I need a new transmission? Check engine light came on 5 months ago, sometimes my car shift gears hard then continue shifting smooth. This happens more frequent now. CODE P0780 Shift Malfunct...