The TC cooler has a line going behind head to drivers side that has rotted and leaks bad now. It hasbeen seeping ,just not noticable. Guy that works at dealer has changed a few and we ordered the parts. The cooler does not show any leaks just antifreeze from that crossover line. Trans has been downshifting from OD then shifting back up, then dropping a couple of shifts. I hope this leak has something to do with the irratic shifting. Its a Goerend trans with all the good stuff so my question is, would a leaking TC cooler cause a shifting problem? It never ran low on antifreeze and I have checked and checked transmission fluid and it looks fine. This cooler ties in with heater core . Truck is down until parts come in then we will decide if I want to switch them out or have them do it.