1996 Cadillac Deville trans shifts hard

Transmission problem
1996 Cadillac Deville V8 Front Wheel Drive 220, 00 miles

Hi, on our Deville, it is cold here and when we just start it and head out the tranmission shifts real hard on the first and or maybe the second shift or so but doesn't seem so hard once its warmed up good. It's probably been 100,000 miles since I had the trans serviced. Could this be a filter clogged up or what would you think? The fluid doesn't smell burnt or anything also. Thanks, WC