lurching when kiced into overdrive

What is your question?

hello my auto repair family! I have a 94 k1500 4x4 5.7 350 v8, just noticed when driving in OD and kicked into passing gear (automatic tranny) it feels like the back in is lurching and not shifting smoothly, runs drives well when on city streets or just slowly accelerating, and not trying to pass fast. was wondering what I should look at or do to "fix" this problem, am thinking about a half bottle of tranny lucas which took care of a simaliar prob with a escort I had a few yrs ago. Any ideas and tips would be great!