[StangLx50]

I read somewhere that you can change all of your tranny fluid by putting it in neutral while hooking a hose up to the tranny fluid cooler return line and emptying it while you fill it at the same time while the car is running till it changes color. I know it can be done but is it safe to be done or will it put too much stress/break something in the tranny?? Mine is in desperate need of a full change. Any help would be great thanks!

[GTRaptor]

That way you would change only part of the fluid.

It is better to drop the pan and install a new gasket and filter.
You will also need to rotate the converter until you see the drain plug and empty it.

It is not hard, but you need a pair of jackstands or some ramps.

[GT50]

Is it safe? Well it all depends if you can keep up with the fluid that is coming out. I personally would NOT take this route.
IMO I would by a filter and gasket kit and change the fluid by removing the pan and replacing the filter. The torque converter, at one time had a little drain plug. I can't honestly tell you if it is in your application.
I say this because just by dropping the pan does not remove all of the fluid. Some is still in the torque converter,lines, and cooler.
If car companies would install drain bolts in their tranny pans this would make life alot easier. Dare I say alot of imports have this!
It would take the equivilant of 3 attempts of dropping the pan to fully exchange all of the fluid.

[StangLx50]

I did the whole filter and pan fluid change last year which is why i kinda don't want to drop the whole thing again. I thought the cooler line way did get it out of the torque converter eventually but you guys make it sound like it doesn't? Well thanks for your help! Maybe i'll just have to wait till i get enough ambition to do another change.

[GTRaptor]

It wont hurt, but not all the fluid will be changed as the new one will eventualy mix with the old.