C4 transmission plug identification

[tempestairbrush]

I have lost the plug on my transmission while rebuilding it that is inside the red box on this picture and it looks to me like it is just a normal plug. Does anyone know if it is some kind of special part that has to be in that hole or just a standard plug to stop ATF from leaking out? thanks\

 

[Don C]

I believe that is a plug that is removed to run pressure tests.

 

[tempestairbrush]

I believe that is a plug that is removed to run pressure tests.

Thanks that is what i was kind of leaning toward being i pulled a similar plug off a FMX transmission in the same location on that transmission i had laying around the garage to replace it. Just wanted to make sure before i started it up and damaged anything inside after it was just rebuilt and couldn't find any info on the internet about what it actually does.