Transmission cooler

I have a 2004 Sport Trac 4.0. It has a factory transmission cooler but I was told by a transmission shop that because of age and trans being rebuilt I need another transmission cooler because original is probably full of junk and clogged. Question, do I need to remove the old one or just add a new one in line with the original?

 

[justgetinstarte]

If it truly is full of junk than I wouldn't want to run it online with the new one. I really do doute that it is, and if it is a good trans shop can flush it for u if it's not rotting away, or leeking.

 

[zach613]

buy the biggest one you can fit in their. i put a ten inch inline after the factory radiator cooler and external cooler.

 

[chefduane]

You might also want to put in an inline Magnefine filter that I know is available.

 

[Josh P]

If the cooler isn't rotted out, install the inline filter chefduane mentioned. If it was mine I'd crack both lines to the cooler and back flush it. Why fix it till you're broke....