It has been proven time and again how tempremental the pumps on 3rd gens are to foreign and native contaminents. I have never seen or heard of anyone in any application for a fluid power system imply or suggest that a given system could not benefit from some type of filtration. The only absolute is that no filtration is the worst way to go.

As well, discoloured ATF can most definitely be the result of contamination besides thermal breakdown. It is very difficult to completely flush these systems of dirty oil. You only have to muck around with the hydraulic systems on these trucks a couple of times to understand why a filter on the suction side of the pump starts to look like a pretty darn good idea.

 

I've installed the MAGNEFINE on several vehicles (not CTD) along with a small DERALE power steering cooler. Easy enough to cook PSF while backing a trailer (or similar), even in freezing weather. High heat in system, and low airflow (vehicle speed + fan speed).