Using only a external transmission cooler

[kurthb]

Transmission cooler lines are starting to leak, due to the salt belt here they are rotted.
Trying to get replacement lines, but thought plan B would be just to run a small external cooler.

Thoughts? I know doing this can make the fluid run too cold but if that is the only option, thinking the smallest cooer I could get would be ample enough?

Also at idle there would be no air flow unless the fans kick on.

Thanks!