I was installing my gooseneck hitch tonight and when I was under the truck I noticed a cooler mounted right in front of the fuel tank. Is this the transmission or Oil cooler. I have never seen one mounted in a location like that.

Fuel cooler. I think, due to the nature of the common rail fuel delivery, fuel temps rise to fairly high levels. On return to the tank, cooling is required. I too was surprised the first time I saw it, and it made me think...

hmm, never heard of that. I'll have to climb uder mine.. but if there is one its probably a fuel cooler judging by its location. Oil and tranny coolers "usually" go right up front

Yes it is the return fuel cooler. The fuel is used to cool the injector controler, the injector pump, and the injectors.

The primary tranny oil cooler is in the passenger side of the radiator, the secondary is in front of the stack.

The lube oil cooler is inside the engine by the oil filter.

Jim

Is it a bad idea to run low on fuel, on hot days?