do i need a sway bar for my 6.7L 2500?

More than likely your vehicle already has a sway bar. This is normally meant for performance and stability, but can also help when towing to stabilize your load in transit.

If you're towing often, then YES! A sway-bar will make a world of difference! If you tow alot, then you might also want to look into a rear air-ride/load-level setup. A company called "Air Ride" offers a make/model-specific kit for our trucks. I have a 2007 Ram 2500 Sport, with a 6.7L Cummins and a 6-spd. auto in my truck. However, I am going to have to put an air-ride kit on mine, because I have a 6" Fabtech suspenion lift, and 38" x 15.50" Baja Claw Radials on 20" rims. So, I am going to have to plant the rear-end down when pulling my 30' gooseneck. Our 2500 trucks are already equipped with fairly stiff suspension. The same as a 3500, minus an extra set of "over-load spring-packs" mounted on top of the "primary" rear spring-packs (which are the same as ours). However, you can add-them to yours, if you go to the dealership and purchase the (Ram 3500 over-load spring-packs, 3500 rear leaf-spring center-pins, and 3500 u-bolts and nuts). The front 4-Link has a 1-1/2" sway-bar and a 1-1/2" track-bar, that works pretty well to prevent body-roll (sway). I am going to add the extra "over-load" spring-packs to the rear of mine as well as the "Air Ride" load control setup. You might want to check that stuff out. I'm no expert (but i've been messing with trucks my whole life), so don't just take my word for it, go check that stuff out, and pick and choose to see what suits your needs best. Good luck with everything.