GeoBoy wrote:
BenK maybe on to something with that engine radiator. I installed this in my 2007 3500 with the 4L80E transmission, https://oregonperformancetransmission.com/product/LNG-47391.html. The factory transmission coolers on the 4L80E were marginal at best.
GeoBoy, that is one of the best types of low PSI, stacked plate radiators out there. Best if the connections between each plate is brazed together and think this vendor does so
Those which have gaskets, tend to leak over time. More so in dynamic applications with vibration. Solved by brazing the plates together with past filled with brass & heated to fuse them together...they even had upset areas on the plates that touched the other plate to lessen ballooning of flat surfaces in higher PSI applications
OEM stacked plate types are good, but not as good as this type of stacked plate (flattened round tubing)
I'm of the opinion to have as much external aux ATF cooler as you can stuff in. Main caveat is that the ATF must also be plumbed into the engine radiator and in extreme cold, a by-pass to remove the external aux cooler
'Was' going to install a larger external, aux ATF when still owned the 8.5K lb boat + trailer and my 7.4L continued to get hotter and hotter while towing. Until it also heated up just commuting to work (32 mile one way, Silicon Valley can get really hot during the summer and fall), which meant something else was wrong
Installed a severe duty fan clutch thinking it was going bad. Instantly cooled it down for a while, but then it started to get too hot again.
Turned out to be plugged radiator from DeathCool (Dexcool and coined it because almost lost the 7.4L). Had the OEM radiator rebuilt (new plastic tanks and rod'ed out the core). Still have the modified 180*F thermostat in there...think it's #3
Then never needed the bigger external aux ATF cooler. Will do so when I rebuild the 1996 Suburban. As the 7.4L will be 'built' and other goodies that will increase the BTU's to be rejected
