The most I pulled with this truck was a 20ft prowler tandem axle travel trailer with my portable welder and couple hundred pounds of tools in the back. 4th 1.00, was great for rolling hills and the like as I it was plenty low enough that I didn't have to shift much. It did most hills in 3rd. and on one 7% grade I had to shift to second near the top. It may have done it in third but it was floored and smokey for some time already. If I were towing more often, I would actually not consider installing an overdrive unit. I just want one for empty highway driving. Which I do a lot of. I want to do around 1500-1600rpm at 55 instead of 2000rpm.
How much are you spending for your Ranger?? Sorry if I missed that somewhere.