You've confused your opinion and preference with facts.
The reason manufactures don't offer manual tranny's is there no demand for them anymore. The modern auto is superior in every way .. almost all heavy/commercial equipment is going the way of the auto. Just the reduction in shock to the rest of the vehicle that a auto offers is worth the heat you have to address. My sons a diesel equipment mech.,my dads a retired Cummins mech. and owner of a small trucking Co..and I even spent 4 years as a apprentice master mech. so I've seen my share of exploded gearboxes... The little 4BT/6BT/ISB Cummins in stock form can destroy a NV4500/5600 with just a little too much hard shifting. Dodge had been the lone holdout with the manual and they where only offered in detuned trucks because they got tired of warranting all the busted transmissions/transfercases/driveshafts and ring&pinions.
Jeff, it sounds like you're confusing your own opinions and preferences with facts as well, if you're seeing that many blown up gearboxes, busted transmissions, transfercases, driveshafts and ring&pinions, then either there is a component quality issue, or a driver quality issue. If your Dad's small trucking company is seeing that many (ANY) blown up gear boxes, he seriously needs to screen his drivers better.
I have been a truck driver for over 30 years, 29 of it tractor trailer, and the ONLY time I EVER Blew up/Broke any of the above mentioned items, was in a GAS ENGINED. AUTOMATIC TRANNIED Pick up with a 11' camper in it, I was young pulled up i front of the house, shifted into reverse, and "Goosed" it a "Little to Hard", yeah, the ring & pinion went, NO Manual transmission involved.
I have only had the misfortune to drive One tractor with an automatic, for 2 days, and there have been few trucks in those 30 years, that I was as Happy to Park and walk away from as that one. I shift clutchless, WAY smoother than the smoothest shift that POS EVER made. The first 14 years driving tractor trailer were doing foodservice deliveries, delivering to Burger King, Arby's, Wendy's, Arctic Circle, and Burgerville's, all over Oregon, Washington, Northern Californicated, and Western Idaho, 8-12 times a day, in places a truck was never meant to be. If just maneuvering a 48' trailer in those places didn't teach you good clutch and shifting habits, it being a 3 compartment FLOOR load, not palletized and wrapped, DID, it doesn't take too many 40,000# loads of messed up groceries to teach a driver, the finer points of smooth truck handling.
As far as "almost all heavy/commercial equipment is going the way of the auto. " maybe in your Dad's small company, but not the companies that I have talked to, with the exceptions of some Beverage distributors, smaller side loaders, and farmers, because many of the "Migrant Farm Workers" WERE tearing the hell out of the equipment, but that is a DRIVER ISSUE not an equipment /component issue, My step Father was the parts dept Manager at Roberts Motors, (Now Pape) the Portland Kenworth dealer for Many Years, and he told me about the trouble with the farm workers.
If your equipment is suffering so much from "Shock" then again, it ISN'T a Component issue, it is a DRIVER issue, what is the Name of your Dad's small company, so I can add it to the list, topped by SWIFT, of trucks to be wary of out on the road.
Doug
30+ Years, 3,000,000+ miles Moving freight from Point "A" to Point "B"