I have a 2008 Dakota with 4.7 and 4 X 4. I have a leaking transmission cooler line. Two questions: how do you get the special connector off the radiator and transmission and #2 what does it take to get the replacement line up and over the front axle? It looks like a very tight fit to get it over the axle.

 

It is most likely of the quick disconnect type similar to those used in fuel or a/c lines. You have to release the garter spring that holds the fitting together by slipping the tool into the fitting to spread the spring or clip simultaneously pulling the line apart. The tools are available at most well stocked parts stores and tool distributors.More info and illustrations similar to yours can be found here; http://dodgeram.info/tsb/1996/21-15-96.htm

Sorry, I've never changed a tranny cooler line in a 3rd gen. If the leak is in an accessible area the deteriorated section can be cut out using a mini tubing cutter and a section of fuel hose clamped in place to stop the leak.

 

I cannot remember the trade name for what the clip is called. There is a plastic cap over the clip. Use anything to slide the cap back. Underneath is a simple u clip / c clip type thing on the line. Remove the clip, don't loose sight of it as it snaps off and goes flying. The line then just pulls straight out.