If budget allows, look at either the Hensley Arrow hitch or the ProPride hitch. Both use a unique 4-bar linkage design that uses geometry to move the pivot point of the hitch to a point above the rear axle of the truck. This gives you the same or better towing stability towing a travel trailer as you had with the 5er. Even though you have a HD truck, I would still recommend for a 34' trailer.
Second choice would be the Reese Straight Line (dual cam) hitch, but the weight and balance of the trailer is more critical for a smooth sway-resistant towing experience.
We chose a TT over a 5er because we find the Suburban more useful for non-towing duty than a pickup truck.