Having owned several Ram / Cummins trucks I can speak to only them. My current truck is a 2012 with just shy of 140k miles on it.
We tow a 5th north and south on I-75 all summer. The truck has never not done the job. I do take great care of the drive line it. Every spring I do a complete trans service through the cooler lines, and replace both trans filters.
I also open both front and rear diff and clean them and replace the fluid as well as drain and fill the transfer case.
Both fuel filters get changed out every 10,000 miles and when the oil change light comes on I use Shell Rotella T6 full synthetic 5w-40 oil in it.
Every 67,500 miles its due to have the EGR cooler and valve removed and cleaned, I had the dealer do it the first time, and the 2nd time I did it and also changed out all the coolant. Its been a great truck and continues to be a great truck but they all are only as good as you treat them.