Manual vs Automatic transmission.

Get it while you can. They won't last long. Before long they will be the floppy disk of tranny's. Before long they won't be able to pass emissions tests.

The '11 Dodge/Cummins has the aluminum case G56 6 speed manual tranny (around 280-300 lbs with a clutch).
gears are
1st..5.94
2nd..3.28
3rd..1.98
4th..1.30
5th..1.00
6th..0.94 OD
reverse..5.42
The Cummins has the zero throttle launch . No slipping the clutch just let the clutch out and the Cummins throttles up on any slope and you don't even touch the go pedal to get it rolling.
My '03 5.9 Dodge Cummins HO has the cast iron NV5600 6 speed manual (about 400 lbs with a clutch) 3.73 gears with about the same tranny gear splits. When empty I launch in 2nd...shift to 4th...and then 5 or 6 depending on highway speed limit.
I've had the truck since new and find the Cummins/6 speed manual/Jacobs exhaust brake is a towing dream. Exhaust brake works in all 6 gear and even reverse.
I would advise you to drive it for a while. There a big heavy tranny and shift nothing like a 3-4 speed manual tranny in a car/1/2 ton truck so there not for everyone. It does take a lot of foot/arm and brain coordination to make seamless up and down shifting without knocking the U joints out.

I have driven plenty of manuals. They work fine but I sure like auto's now. So does my knee. But I am 60. :)

The manual has been great to me - it's always in the right gear! ;)
The only time I don't like it is if I get stuck in stop and go traffic for hours.

One of the reasons that manuals have died in light and medium duty trucks is that you need a very, VERY low 1st gear to get things moving. Frequently 1st is not used except for hauling or towing. Then you need 5 or 6 speeds to try to make up for it on the other end.

Automatic transmission torque converters provide a huge boost of torque at very low speeds.

My Dodge is a 5 speed manual. I drive it through town, dealing with all the stop lights, quite frequently.
I would really like to change it to a 6 speed manual, and change the transfer case to a 242HD unit.
I wish my PT was a five speed manual.
HMMMM... I wonder... could I put a 6 speed manual in the motorhome, using the shifter from a COE truck?
All that is required is time and money!

"Not looking for the "weight police." I don't believe weight is an issue but why attempt limit comments? Unless you are seeking validation.

I chose automatic transmission. When I want to "shift" I can via my Chevy's Mauual Mode. Others have similar systems.

I loved the 6speed ZF tranny in my 7.3 F350. Low hole for getting going and without a load shifted it as a 3spd. If you live in an area with a lot of stoplights it can make you think about a automatic. No problems towing with one.

Growing up my father had some trucks and they all pulled a good load with a standard shift. In the teamsters I made 25 or 30 deliveries, sometimes more, and a half dozen pickups with a 40 ft box every day and it was always a standard shift. The transmission never gave any trouble.