First, the od light started blinking. Is not blinking anymore, but then the transmission began having problem. It not engaging right away or when shifting from drive to reverse it does not engage right away. It may take almost a minute to engage. Something is very wrong with my vehicle.

Since the CD4E, 4-Speed transmission filter is not serviceable, without the transmission being disassembled, the transmission may be full of crud. Try dropping and cleaning the pan and changing the fluid (Mercon V) several times. If this does not help, the ATX likely needs rebuilding. Personally, I would change the fluid every 30,000 miles, using Mobil 1 Synthetic Multi-Vehicle ATF.