Brand new Bronco Owner-83 302, C6. After I got it tuned up and running smooth I took it out for a cruise around town. After 15 minutes I could smell a distinct burnt oder, like cooking fluid, and it seemed to be in the center of the truck. The trans fluid was a little low so I added a quart to get it "between the arrows" which seemed to help a little on the way home. Next day I dropped the pan and changed the fluid and filter. The fluid was clean and red and the filter looked new--making me think somebody else tried this not long ago. On the next startup the trans shifted better cold, with a good "thunk" between gears, but got sluggish when warm. After a 20 minute trip and sitting for a few minutes, I started it up and put it in Drive and it felt like the handbrake was on (it wasnt)--it moved out OK after that but the "thunk" seemed to have gone away. During normal driving it seems OK to me but I still seem to get a little smell. I know NOTHING about automatics--any thoughts or diagnostics I should try? Any advice kindly appreciated, also feel free to let me know what pertinent info I have not mentioned. Thanks.