I have a 1990 Troopr with a 2.8 v6 and a 4l30e transmission. It doest shift up to 2nd gear until 25 miles an hour, and doesnt shift into third until it hits 3200 RPM! Also when slowing down with my foot off the throttle the transmission downshifts very roughly. I was told by somebody that it is just an ancient transmission that us preprogrammed to shift at different set RPM levels. I have trouble buying that however. Is this normal? If not what should I do?