Hello. I'm new here and have a '03 Lincoln LS with a 5R55S that's having issues. My wife's '03 LS V8 has a bad shudder in and out of 4th gear and hits third pretty hard sometimes. In fact it will even chirp 3rd at WOT. It does work properly at times, and does hit all 5 gears even while malfunctioning.

The trans shop thought a PCM reflash would fix my issue. It didn't. The dealer said the flash took a long time, but the issue is still there, and the trans seems to be ok electronically. There are no codes. Any ideas what it could be? The pan has been down and was clean. I know the TC has been an issue on some of your cars. How do TC failures show themselves? There seems to be discussion of these issues than I see on LS forums. Thanks for your time.