Transmission Cooler?

As supplied aluminum tubing is in the fully annealed condition, so fatigue hardening and eventual cracking are my biggest concerns with it. My RoT's are rubber lined Adel clamps no more than 18" apart with a bulkhead union fitting that is stuck thru a tab, panel, or bracket at each end of the tubing. No tube ends hanging in space and no long unsupported sections. I always place the bulkhead unions where I need to make the transition from tubing to hose (usually to deal with relative motion), like where the cooler lines would jump off the chassis to go to the trans. Following those rules I've never felt disadvantaged in using aluminum.

For trans cooler lines they would be a better choice than steel for at least one aspect, aluminum transfers heat much, much better than steel. the cooler lines would, in effect, be mini-coolers themselves.