Transmission cooler line connectors

[GerGa]

My transmission cooler lines are starting to leak at the flex-to-rigid joint so it's time for new lines. The car is a 2004 but I should be subscribing to 2003 car's connectors because I figured out that I have a 1/4-18 return fitting(transmission side, screws parallel to ground) when I had to replace it a couple years ago.
The 1/4-18 return fitting belongs on cars built prior to January 19th, 2004. So, according to Triple Edge Performance I also need a 3/8-18 feed fitting w/check ball LINK: http://shop.tripleedgeperformance.com/4 ... 213958.htm.
That takes care of the transmission end of the lines, but I don't know about the radiator side.
Dorman calls out two fittings for radiator side: part number 800-605 with 5/8-18 threads, and 800-721 with M18x1.5 threads.

Can anyone confirm if Dorman is right? I am surprised one fitting would be standard and one is metric.
Dorman link: https://www.dormanproducts.com/gsearch. ... 0Connector
Thanks

[maxi426]

Use GM parts. Give dealer your VIN, and they should give you the correct parts. Fit is better than aftermarket also.