My father and I are in the process of buying a 2001 3500 quad cab with auto trans. We are planning on using it to pull another trailer from AZ to OH.
We were told it has a factory trans cooler but are not sure if this will be enough to keep the trans alive towing. I'm guessing we will be pulling close to 12k.

 

I've been told by a couple diesel tranny experts that the Dodge tranny cooling system is excellent and really needs no improvement.
There are two coolers, one up front and a engine coolant to ATF one on the block.
Keep the front one clean of bugs and your fluid in good shape and you'll be fine.
Some folks who tow heavy often like installing an aftermarket pan that increases capacity 3-5 quarts.
An aftermarket trans temp gauge is a good idea too especially if the engine hp has been jacked up.

 

Thank You infidel for the input.

 

I added a B&M trans cooler with the fan for stop and go traffic. Now with the fan off driving down the road, the trans temps average 5-10 degrees cooler. With the cost of a trans rebuild, I did everything I can to make this one last as long as possible.

 

I towed thru AZ and by Death Valley in June, it was 120*+ and tranny temps were 190* max. Change the fluid/filter annually and you s/b good.

 

Thanks again. My father and I are going to be leaving AZ soon for OH.
Stick a fork in me I'm done with AZ. Looking forward to some cooler weather and change of season's.