904 Leaking. What to check first?

I uploaded the screen shot for the tool. Pricey at $50 but I’d rather pay it and try to take the seal out as opposed to removing the pan, drain fluid and remove valvebody.

Here is the link:
https://www.amazon.com/dp/B011SBJSHA/?tag=fabo03-20

Also the screen shot for the seal I purchased. From my research it was Mopar # 3878447, however, has been replaced by new #4505098.

Hope it works.