hello everyone. I have just made a trip from Wisconsin to Texas in my 2002 express 3500 6.0 gas v8. I was towing my 30 foot travel trailer (right at 5500lbs).

The van did great overall. I would eventually forget the trailer was even there. However. When going through hilly terrain the trans and coolant temp would spike. Coolant temp got as high as 221, and trans temp got to a max of 210. This was at 60mph. I would start the climb at 65 and be doing 50 by the time I hit the top. It's not that I couldn't get to speed. I didn't want to push it. Trans was kept in drive (seemed to run cooler this way rather than keep it in 3rd). I have an auxiliary trans cooler (although it's pretty small)

I am looking into an aftermarket radiator. I feel that the trans temp only climbs because the coolant temp is. I cannot seem to find any radiators for a 3500. I have found ones for the 2500. Are they the same? Can anyone point me in the right direction? Thank you!

 

Check RockAuto, they have several stock types, don't mention upgraded. Don't see a 6.0 for 2002, only 5.7 and 8.1 gas.

 

Looking like I have to select 2003. Maybe I'm a year off. What's the difference with a 2500 and 3500? I can find several for a 2500 but no 3500's.

 

I see several for a 2003 6.0 3500, on RockAuto.com.

 

Checked through the ones they have available. None of which look to be any better than my factory one. Guess I'll just start with a bigger trans cooler

 

I have over 75,000 miles towing a 10,000 lbs trailer all over this country with my 2006 Express van and at some hills my speed was topped at 30mph! I had exactly the same issue. You don't need a new radiator, you need a new fan clutch, I suggest severe duty Hayden 2786. That's what I run and engine temps are always stable. The transmission will still run hotter on hills with trailer. Solution for this is a second, or bigger trans cooler and/or a deep pan. Look up Derale 14207 for example. The deep transmission pan allows you to have larger fluid capacity and has channels for cooling. If you really need it or not depends on how often you are towing (in the Arizona mountains during the summer)!
http://www.rockauto.com/genImages/93...SD-HD-SVRD.pdf
The fan clutch lasts about 30,000 miles when towing and the easiest way to undo the old clutch from the engine is using an air chisel. Then it's a piece of cake.

 

This is my thread from last year before I learned about the fan clutch: Cooling options for Express vans? - Chevy and GMC Duramax Diesel Forum

 

good post Artie1

when people want to add supplemental coolers to their vehicles its a head scratcher. if it's overheating, either something is wrong or your working the vehicle past the demands it was designed for. putting a bigger heat exchanger doesn't fix the problem only the symptom.