Sorry I don't know the TSB number. I remember them saying something about a valve body. The part was on national back order and I had to wait several weeks to get it fixed. Hard to believe a dealer doesn't know about this issue unless they are very small.

 

And I thought I was imagining it........
Mine has done this for some time and is getting worse.

 

You guys should check the rooster comb and detent ball. When I had my trans rebuilt The vavle body that I got had an edge of raised metal on the comb and it chewed the detent ball up. There is also a sharper ramp on the comb coming out of park. I noticed mine getting harder and harder and then all the sudden I couldn't get it out of park at all. Luckily it was in my driveway. This was about a month after having the trans rebuilt. I ended up taking the valve body out in the driveway and taking it to timinva, and he hadn't ever seen anything like it. He reworked the comb and took the raised metal off and it has been working fine ever since. I think the comb was even harder metal than the detent ball.
We found a way to get it out of park after I got the valve body to Tim. If you hit the shift lever on the trans with a bfh it would shift out of park and then through the rest of the gears. But if you put it back in park it locked up again.