For my 2 cents, if you use a big enough cooler, you can skip the plumbing to the radiator--it only complicates the installation and the engine will run a tad cooler without the transmission fluid flowing through the radiator tank. I have a 3500 converter in my '68, which is very loose and creates a lot of heat. I used a heavy-duty 7-tube aftermarket RV cooler and it works fine on my car. But by all means, use an auxiliary cooler! A 2400 converter isn't that loose, but on a hot day in traffic you'll be glad you did. Heat kills an automatic transmission. Mount the cooler in front of the radiator in the airstream. Good luck!