My father had two of those 7.3s One was a turbo and one wasn't. I remember the non turbo as being a dog. Thats why he traded it in to get one a few years newer and with a turbo. He pulls a 31' 5th camper. I know he had to get the automatic transmission rebuilt at around 100,000 miles. The transmission shop told him his was common on the 7.3 automatic trucks.
Never had any engine trouble.