1998 Rodeo Transmission problem

My 1998 Isuzu Rodeo consistantly has transmission problems. It's had 2 rebuilds and a replacement just in the last year and a half. I recently went on a road trip (abt 500 miles) and now it feels like it won't engage in first gear. The whole car shakes really bad when starting from a stop, but it's fine once I get going. What could be causing this, and why does my car seem to eat transmission? Also, the check transmission and check engine light go on every once in a while, but every time I've taken it in, there's been no problem. Has anyone else had problems like this?

Thank you!