Ford AOD cooling line thread size

[rspears]

I think they had 5/16" push lock fittings from the factory, but many leaked and had a Ford OEM adapter installed later - http://www.latemodelrestoration.com/...Line-Connector
I don't recall the size, but if your 1/4npt goes in finger tight and stops before it bottoms out I would bet that is the right fitting.

[roadster32]

All Ford auto's use 1/4" NPT threads in the case

[32steel]

All Ford auto's use 1/4" NPT threads in the case

Thanks for confirming what I suspected. As I said in my post I can thread in a 1/4 NPT fitting finger tight, did not want to tighten it in place if it was was not the correct match for the threads.

There is a huge difference between an 1/8 NPT and 1/4 NPT and no way could be confused to have been an 1/8 NPT. The threads are fine and there is no need to chase the threads, that is the last thing I would want to do and run the risk of putting crud or possibly chips in the tranny.