The Long Bed Heavy Duty trucks do have what we often refer to as a carrier bearing, the FSM refers to it as the center bearing, and there is a procedure for replacement.
I don't see any mileage listed for your 2500, but mine has 105K on it now, I replaced all my driveline u-joints on mine this past weekend. It was a Pain In The ***!!! The double cardigan gave my fits--took 4 times of disassembly--assembly before I got it right. I have the short bed version and do not have the center bearing. If you do decide to approach this on your own, I strongly suggest doing all your u-joints, get greasable ones--the are made by federal-mogul and are available at NAPA under the precision brand. The front yoke joint is one of the toughest I have ever encountered for pushing out the old bearing caps. I has the plastic injected retainer ( much like a staked u-joint---no clips to remove). I ended up cutting out the cross with a 41/2" grinder and a cutting wheel then was able to push each cap out individually.
I would assume that the center bearing is available at napa also, plus new clamps for the slip yoke you will have to pull apart in order to change the center bearing.
Good Luck, lets us know how it goes---Glad mine are done--so is my wife, I can be unbearable at times like that