Towing a 3023 with a 2000 Dodge RamVan

Has anyone had any experience towing a larger TM with the Dodge 1500 Ram Van. I have been towing with this vehicle for about a year. The van has the 5.2L with factory tow package and upgraded trans cooler. My concern is that the vehicle has a 3.55 to 1 gear in the differential and the van seems to have poor pulling power once I leave the flat state of Florida. Has anyone upgraded to the 3.95 gear and if so what is your opinion. This question may also apply to the 1500 Dodge Ram P/U since I believe that they both use the same platform with just a different body.

Thanks

Woody