I am having a similar problem with my 2000 Country Coach Intrigue with ISC 8.3 Cummins (350hp) / side radiator with 82000mi.
The transmission cooler began to leak and when the shop removed the CAC and Trans Cooler (1 unit) and is mounted in front of the engine radiator. We found between the two was a mess of debris that was probably the cause of the trans cooler failure. The engine radiator was also full of debris and the core is rotting. I believe the debris was the cause of the trans cooler failure. Also, I don't see a way to clean out this area to prevent future problems after reconditioned.
Any advise as to cleaning the radiators and in between them in the future. Hopefully without disassembly?
Any help as to what this repair should cost, with reconditioned CAC, trans cooler reconditioned with new core and engine radiator reconditioned with new core?
Input / advice appreciated.