1998 Buick Lesabre auto transmission problem/question

I just changed my tranny fluid and filter on my 98 lesabre @ 94,000 miles and now I have a slight slip under heavy acceleration from a dead stop.

My local library does not have a manual with relevant information and I can't find a website that helps so if anyone knows of a website that can help, or a band adjustment or something like that I would greatly appreciate it.

Thanks,
Dan