Slipping unless overdrive is off

What about this? This is where one of the circular plates go. I took pics at two different angles so that hopefully you can see that it’s indented slightly.

Can I reuse the check balls? None of them look like they’re worn. They’re all the same size.

I think I found out what that indent was that’s located near where the small circular plate goes. It’s made by the manufacturer to keep the plate from flexing and cracking. It’s only located in that spot, on models 2000 and up according to a video I watched of a mechanic rebuilding the valve body. He said if there are small pressure cracks right there then you need to replace the plate because eventually with more pressure the cracks will get larger.

Can I use this on the transmission oil pan? It’s what came up when I input the vehicle info, but it looks a lot different than the original. Holes line up though.

Or is the original reusable?

The original is hard rubber, but I can't tell if it’s in the best condition. The new gasket is way thinner, but is it still okay to use? Okay cool. That works for me, lol.

Okay, so change of plans. I went to the Ford dealership to ask the service guys some questions. They told me that the cotter pin looking thing goes in between teeth on clutches or something like that and without it it’s going to clunk really loud, and it’s caused by a worn transfer case. And they also said all that sludge on the magnet means the torque converter is going bad so that means a rebuild. Complete rebuild. So, would you happen to have the instructions on that along with a complete parts list? And will I need any special tools? Or should I ask this stuff in a new question?