Transmission cooler lines leaking

[Hamish]

I totally agree that an exchanger adds a risk. 500k miles on the cooler will be when the truck reaches 2,000,000 km, so I will make a note in my service checklists to be proactive and replace it at that point.

I do drain a little oil out of the tranny at each major service interval with the hope that I might notice any coolant leaking into the oil before it becomes big. I probably checked my tranny oil for coolant three times in the month after I installed that exchanger!

I'm OK with the added risk in my case because I turn the truck off to sleep, even outside in the winter down to - 20 DegC. That stiff oil in the tranny pump blew the air exchanger hose right off after starting the truck and I would have lost my tranny due to no oil in short time if I had not done a second loop on my pretrip and noticed the rapidly growing puddle. Love having a warm tranny a few minutes after starting the engine (Espar engine heater). The truck was starting to slip out of gear under heavy load when I first got it at 910,000 km with original tranny. Used to hold it in gear, just in case at times. Changed the oil, (synthetic of course) and figured I would have to have it rebuilt as soon as I had some down time. That truck/tranny is now at 1,313,000 km and no more tendency to jump out of gear at all, which really surprises me.