Lots of good suggestions here. You will have to go through each step in some sort of order. I will throw my two cents in. Is there anything that could be putting a load on the engine causing it to do too much work? Something that maybe would ease after a few miles. The trans problem seems closely related, maybe a converter problem. Maybe the parking brakes take a little time to release. Check the rear end after driving for a while. I've seen some that glow red they drag so bad.