If you have a problem with your Odyssey transmission, typically you should take it to a dealership to have them diagnose the problem. The thing people first notice is slipping between 2nd and 3rd gear. And maybe your check engine light came on after a slip occurred.
Just a few pointers if you decide to tackle your own honda automatic transmission rebuild. Get a helm and get a rebuild kit with steels. As your steels will probably have hot spots. I got my kit and torque converter from CT Powertrain. Talk to Sean, very knowledgeable about what breaks in these things. I’ve done a ton of honda 5 speed manuals, this is my first honda auto, I do have some turbo 350′s and 400′s under my belt.