My truck over heats when pulling my trailer

[Dartnabout]

OK I bought this 97 Dodge Ram 2500 with a 360. When I pull a load it overheats. I had the radiator checked cleaned and flushed by a rad. shop aand he said it was fine and not plugged. Nest step was to replace the pump and Thermostat. Stil over heated. I found out that it over heated for the guy before me and he put in a pump and thermostat so it has had two new pump and thermostat. Now I take it to a shop and he tells me that exhaust is getting in the water. so off come the heads. they are reconditioned and checked for cracks good to go. I put the best head gaskets available on. Still heats up. I replaced the viscosity fan. Still heats up under a load. What next I am out of ideas? Even though the shop said the radiator was good it is the only thing not replaced...oh I even replaced all the hoses including bypass hose. lam at a loss here any suggestions?

 

[Dartnabout]

Oh the truck has 65,000 miles.

 

[Mopardude]

Do you know if your truck has the tow package? I have heard guys with 1500's with those late 90's trucks that didn't have the tow package so they didn't have the upgraded cooling that the package offered. Which gives you an additional radiator for the trans. Being that you have a 2500 you would think that should be a standard option for your truck but you never know. Other than that not really sure what to tell you. Out of curiosity what are you running for oil and brand of spark plugs and how much weight are you pulling?

 

[Dartnabout]

Believe it or not it was the radiator. I watched the guy flush it and the water flowed then. So thanks for the reply.

 

[Mopardude]

Could have had a chunck of rust or something in it and it dislodged when he flushed it and fell back into place after.