Was shifting from reverse into drive and my montero would not change gears. I could change into park and then into drive. But, the 'check engine soon' light went on as well as the center differential lock light went on. As I drove the last 2 miles home, my truck stayed in one gear and did not shift as I increased speed.

Any thoughts on what is wrong and what I might be able to fix myself?
A

 

Have you EVER checked trans fluid? Have you EVER changed trans fluid? Good place to start.