The only thing you can do is check to make sure you didn't split the gasket, check the transmission case to see if it is flat and there are no hairline cracks, and take a ball peen hammer and slightly peen the bolt holes on the pan away from where it mounts. Also, check to make sure the new pan is true.
I'm confident that isn't what you wanted to hear, but it has to come off again to determine the cause. You can try to save the fluid.
Let me know what you find.
Saturday, May 18th, 2019 AT 8:44 PM