You pull BACK on the black part and PUSH the line INTO the cooler then PULL the line out (the whole time you are pulling the black part back). They can be a little finicky...I added an engine oil cooler on mine...didnt get the line in all the way and it poped out while i was driving down the road....needless to say all 7 quarts dumped out of the engine in about 2 seconds...luckily i noticed the oil drop imediatley and pulled over....so make sure you get them back on correctly when your done.
Use a little WD-40 to work the black connector back and forth.
I dont think you will be able to replace that connector easily, the easier route would be to get a used set from a part of the country that doesnt get snow/salt.
03 DII 80K, 2" OME +1" spacers, CDL, Tom Woods Front Drive Shaft, Tactical Rovers Diff Guards and Rear Bumper, RTE Sliders with Nerf Bars, Rover Tracks High Clearance Tie-rod and Drag Link, Extended SS Brake Lines, 285/75/16 Treadwright Backbone, Glowshift Sandwich Plate - Oil Temp and Pressure. Dual Truetracs with 4.43 Gears from GBR
. Warn 9500 sitting on the garage floor...