Any 727 experts have some advice?

Got in my truck this morning and left for another 12 hour day at work. Truck was running fine when I parked it Last night. Got in this morning and now it doesn't shift into drive until about 45 or 50mph, and when I coast it feels like I'm pulling the shifter down into second when it slows to about 25mph. It doesn't seem to slip at all. Just changed fluid and filter about a month ago, and added a bottle of Lucas. Its a bone stock non lock up 727 in a 86 4wd 3/4 ton pick up. Is it a goner or is there something sticking or out of adjustment? The kickdown linkage is set where it's always been, fluid level is correct, and it's always shifted and worked fine until I drive to work this morning. If I'm on the throttle hard it seems to upshift fine. When I changed fluid and filter, there wasn't any debris in the pan and the fluid wasn't burnt, since I change it every 8k miles or so. Any help would be greatly appreciated. I know some of you guys have a lot of experience with automatic trannies