my 03 has a coolant underneath the car coming from the metal hose that goes from the radiator to the oil cooler, my question is do i need to drain the rad before i attempt to change this hose?

 

is it really coolant leak or just transmission fluid leak? Since the Radiator itself is sealed and the tranny cooler is built into the radiator which is self contain. So answer to your question depends, what is leaking. if it's a coolant leaking, then you need to replace the radiator since you might have a crack or rupture on somewhere. Now if it's just tranny fluid, which you should know by now it's red, then no needs to drain the radiator but try to find out why it leaking, is it the hose or the fitting is seeping?

 

The rad was replaced already correctly it's definitely leaking coolant not transfer fluid the leak is from the metal hose

 

check that the hose is not cracked, if that's not the so issue, then the radiator has a small crack. Look for the whistling noise around the radiator.

 

Yes. Coolant will spill out anyway as you change the pipe.