MAXGXE

I put a post on here about a week ago about engine knock during cold starts and I appreciate all who replied but I now have another issue (among others) with my 00 gxe. When cold let sit and warm up for a couple minutes but lately takes longer to shift to overdrive. Searched some prior post but with all the concerns with auto trans I could be here all night. Started up after sitting for a hour and overdrive light flashed between 8-12 times. Didn't get to see happened immediately after startup. Took it back out an hour later but no flashing light. Had fluid flushed from dealer about 7k ago (purchased used) so I should be good with that but just looking for ideas. Thanks for any help you can offer.