I have a very simple question and just wanted more your info. My last 3 cars were various domestic trucks (1996 Chevy 1500 and 2001 Dodge Dakota QC v8) and a domestic SUV (1990 Chevy Blazer- s10). They all had automatics, but depending on the vehicle you weren't supposed to tow in OD or drive, but in some lower gear. I have not seen anything that says that I have to do this with the T4R but just want to make sure. I will be pulling a boat that is +/- 4200# (including trailer and all). Do I just leave it in 'D'?