I have a '93 Dodge D250, 5 speed and just recently pulled a gooseneck RV trailer that weights about 7400 pounds. My gross combined weight was 13,500. The trailer pulled real well between 60 and 65mph, but I was concerned about my water temperature. Towing in overdrive, the gauge (Cl..l l l l..lH) was reading at the 4th (red) mark out of 6, slightly hotter the midway. And I was wondering if this is normal for towing or if that may me too hot for sustained towing. Also, the outside air temp was between 20 & 50 degrees at the time. Thanks in advance.