My 2002 Isuzu Rodeo with the 3.2L V6 downshifted from 4th to 2nd on the highway at about 65 miles an hour to pass and not it is stuck in what I think is "limp mode". The transmission will shift from Park to Reverse and then into Neutral fine and engage the gears. When I shift into Drive the vehicle will not shift higher than 2nd. Also, the dash indicator will only show Park and 2nd. Nothing in between. I have changed the transmission fluid and filter. There was not any large particles in the fluid although it was pretty dark, and had a burnt odor to it. I have checked all of the connections to the sensors to make sure they are plugged in correctly. I also have checked the battery and alternator. The battery sustains about 12.7 volts and the alternator puts out a steady 14.2 volts. Please someone who has any ideas please help. This is my only vehicle so I have to keep driving it to work.