Locked differential?
"As great as the performances of all these old 2wd vehicles were, it was the result of their higher ground clearance and little more"
I think that the low torque output of their engines probably helped to some extent–at least when starting up from a full stop. And, engines used to be placed a bit further back in the chassis, thus giving slightly better weight distribution than modern RWD vehicles (with the possible exception of BMWs).
All good advantages but still can be had in any modern rwd pick up with good weight balance ( by adding weight when necessary) . They are equally capable of going over the same roads. As a matter of fact, If you lift ( add ground clearance ) a 2 wd truck appropriately, add the right tires ( and balance) and rear differential, you can drive through mud like you would not believe.
Insightful, that’s an excellent question. Since the name painted on the door suggests that the car was used around the oilfields and paved/concreted roads were pretty much nonexistent back then anyway, there’s an excellent possibility that the rear axle was locked.
That’s a pretty tough old car. Of course they might have gone through 5 of them making the film… What I find amazing is that the wooden-spoked wheels survived that punishment. I’m pretty sure Dodges of that era all had wooden spoke wheels.
I see wire wheels on the car they flipped over.
There are both wire wheels and wooden wheels in the film. In the scene where they kick the mud from the wheel, it’s clearly a tangentially spoked wire wheel. The car they rolled over clearly had wire wheels. At the very end of the film, where the car is driven up to the oil well, the spokes are radial wooden spokes. I believe I noticed radial wooden spokes on the car going down the steep banken too, but I’m not certain. I might have even seen solid disc wheels in one of those “hill” scenes.
I had years ago a 1936 Chevrolet. It was great on bad roads.
My dad’s lane was 1/4 mile long. There was a sharp turn then a steep hill going out. When it was icy and snowy one took that turn as fast as you could, to get up speed for the hill.
One day my brother couldn’t make it out. So he walked back to the house and put his chains in my car and asked me to drive it there. I stopped back about 50 feet from his car. He cussed me out so I started up again and drove up to his car. No spinning or anything,
And, I could drive it in the woods in places one would not expect to find a car at all.
@irlandes that might explain why we see those old cars in the woods sitting there like they hadn’t been touched in 50 years or more.
As for that Dodge car, if I needed some rocks tumbled, I’d just load them in that car and drive. By the time I got where I wanted to go, they’d be all nice and shiny.
When I lived in my apartment about 10 years ago, the driveway had about a 15-degree grade. On snowy or icy days I used to get going about 40 and slam my car up that driveway. I lived in that apartment over 13 years and learned this technique from experience. I had both FWD and RWD cars during this period, plus a 4WD vehicle at one point that did much better, but would still slip.
One neighbor made fun of me for my driveway approach technique. I sipped a beer while I watched him dig his car out of the snow right in front of that driveway 
Eventually I did go down and help him.