The Old "Butter Box" ACCOs they were very popular over here, the Australian Army had 4x4 and 6x6 versions in the 60s that were built in Australia especially for them and they also sold them to the RNZArmy. They did service in Vietnam and out performed the American trucks of the time. I read a big article about them and how impressed the US army was with them. I'm actually looking for a 6x6 model to restore and make into a camper truck so if any of you Aussie's have one in the back paddock let me know.
As for backing you are wright, we never have to back them any distance but you will get about 15m before they start to have a mind of their own. If you get into a situation you have to break the whole train up and that is a nightmare on its own. This is the main reason for "Side Tipping"
Its unusual for the DCF/ Transtar to have had a Cummins, maybe not here but in NZ they were all 320hp 8V71 Detroit powered, there's nothing sound's like a 2 stroke "Jimmy" in full song. I had 4 Kenworths, the first was a 475HP 8V92TA, the next was a Series 60 420 HP, then another Series 60 at 470HP all Detroits. Then my first and only CAT a C12 410HP. I then bought an International 9900I with a 600HP Cummins "Signiture" I loved that truck, 850,000 km without a spanner on it. When I get home I will download Photo's of my trucks, they aren't Aussie Giants but they are still cool trucks.
Cheers Leon