I think you'll want to upgrade the Cummins for more hp after driving a friends 2001 with the 24 valve. I'm a great Cummins fan and the 2500 should be fine with the load, just underpowered. I tow a 10,000 lb 32' Coachman fifth wheel with my 1500 hemi pretty easily and have towed a similar size trailer with the 01 Cummins Ram and it was much easier with the hemi. I don't think it would take much, better exhaust, a tuner maybe. Perhaps your Dodge dealer can look up your serial number and find out more info on your Ram.

 

Your truck must have been revving pretty high. You were also over towing capacity. Sorry, but I don't buy it. I've had Hemi trucks as company trucks. There's a reason I own a Cummins.

24v trucks aren't the fastest stock, but hook a trailer to them and that's where they really shine.

I forgot to mention that my truck does have a Banks Kit on it. I'd have to get the paperwork out to specifically detail which Banks Kit was installed. At that time Banks offered 3 upgrade kits for my particular vehicle, and I chose the mid-upgrade which did include an all new exhaust system.

You most likely have 3.55 gears. What are your RPM's at 70 mph? And what size tires do you have?

Check this out:
http://dodgeram.info/2001/towing-charts.html
It's for 2001, but nothing major changed from 99 to 01.

 

I forgot to mention that my truck does have a Banks Kit on it. I'd have to get the paperwork out to specifically detail which Banks Kit was installed. At that time Banks offered 3 upgrade kits for my particular vehicle, and I chose the mid-upgrade which did include an all new exhaust system.