Michael, For most "normal" towing the tranny cooler (in the radiator on my 1 ton Dodge/Cummins 4x4 or is a dually a 6x6? with automagic tranny) is fine but for really rugged service an added heat exchanger (tranny fluid to air with thermostatic controlled fan is a good idea.) It will extend the life of the tranny and the fluid. A linear increase in tranny temp gives an exponential decrease in fluid and tranny life once you get beyond normal operating temps. It is hard to OVERCOOL your tranny and using a thermostatic controlled fan on the cooler is a good idea.

It can help a lot in more extreme situations like hot weather, heavy loads, hills, etc and will cause no harm even if it is not needed. I think it is a win win way to go. If you never tow more than several hundred pounds and don't ATTACK steep grades and stay away from full throttle climbing hills (opting for lower gears and lower speeds) then you probably will not gain much from an additional tranny cooler. If you really GO FOR IT then I recommend an additional tranny cooler. If you don't put on many towing miles and trade your trucks in at really low miles then you probably don't want another tranny cooler. I'm driving a '97 Dodge/Cummins that is just getting well broken in.



[img]/forums/images/icons/smile.gif[/img] Pat [img]/forums/images/icons/smile.gif[/img]