14k honestly isn’t a lot of weight for these trucks, the 68 has proven to be a very capable transmission.
I'm on board with this.
If you read posts about this subject matter, you would walk away thinking you need a RAM 9500 with a Cummins ISX coupled to an Allison MH series transmission, 9:56 axel ratios with triple rear wheels to tow 9,000-pounds. OK, I'm exaggerating, a lot, but I'm making a point of some of the ridiculous posts made in threads with questions like the OP's.
I tow around a 15,000 pound 40 foot Montana with a 3500 Cummins, SRW, 68RFE and 3:42 axles. Guess what, I can EASILY make 70MPH on an acceleration ramp to a freeway. And when I'm not out on the road with the fiver, I'm pulling around a 16-foot dump trailer that comes in at 14,500 loaded and still have no issues with the pathetic 68RFE, SRW, and 3:42 axle ratios. I must have a somewhat unique 68RFE, it behaves and shifts very smooth, slowing down in tow/haul mode with exhaust brake on auto is just as smooth and precise.
OP - enjoy your truck, find enjoyment in knowing you saved yourself several thousand dollars by not buying a transmission that has more frequent service requirements, more costly service, and its own set of shifting behavior issues. Follow RAM's published tow weights, payloads, and scheduled maintenance and you are good to go. As far as feeling the additional power, doubtful because of torque management. The additional power would be noticed when pulling heavy, not 17,00 or less pounds.