[leddzepp]

I'm not aware of an OEM external (auxiliary) transmission cooler My 72 is original and the lines run through the heat exchanger on the radiator. It runs at operating temp. with no issues even in the summer months with AC blowing. There is nothing wrong at all with adding an external cooler, as it certainly helps keep temp down, especially if you are towing or hauling a heavy load... but I don't think it was OEM. Your 71 originally had lines running through the radiator.