I have a 2003 Jeep Grand Cherokee with the 4.0 engine. I am planning on doing some towing up to 4500 pounds probably about 4-5 times a month. However, the vehicle is rated up to 5000 pounds with the towing package (transmission cooler and 3.73 axle ratio). I do not have the towing package. Therefore, I have the 3.55 axle instead of the 3.73, but I do plan to get the trans cooler. First, I would like to know what difference the 3.73 axle ratio makes compared to the 3.55 for towing and if I really need it. Secondly, would I be okay with just the transmission cooler and the 3.55 ratio towing 4500 pounds about 4 times per month?