I am an advocate for the fluid exchange using the return cooling line. If you have a thermal bypass valve, you may need to remove it. I have done this method with great success in my Tb, old 2011 Ram 1500, 1993 C1500 and my brother in laws 1995 Jeep YJ, TJ, or what ever designation they were using for that year. The Jeep used some sort of Aisin 3 speed if I recall and the pump only engaged when you shifted to neutral or driving gears.