I have a 1987 Lebaron 2.5L with a broken rod (from overheating). I'm in the process of taking the old engine out and putting in a used one (not rebuilt). All is done but the mounts and the tranny disconnection. My question is how do i disconnect the tranny and torque converter without ruining either. What is the average lifespan (mileage wise) for the 2.5L.