904 trans cooler line fittings
The fittings are known as SAE flare, and are 45* and if you've heard of AN fittings SAE is different. The trans side is pipe thread, as mentioned, 1/8 pipe is about 3/8 OD, 1/4" is quite larger nearly 1/2 OD
So you need an adapter. ANY real parts store should have these, like this......ignore the size it's just for illustration
There used to be several old school companies that list these, weatherhead and Edelmann are two You can download catalogs on the www , and here's one now
http://www.plews-edelmann.com/assets/1/7/automotivefittings_90078.pdf
See page 10 of the above, they are calling this a "male connector." Notice that this gives you not only the Edelmann part no. but Everco and Weatherhead AS WELL!!
Notice that just like AN the size is in 16th of an inch, AKA 5/16 tube is "no 5" and 1/8 pipe is "no 2" So one of these 5/16 flare x 1/8 pipe (ex) is
148520 Edelmann, 48D Everco, and 48x5 Weatherhead.