There must have been some reason why they engineered it to be driven by the rear axle on a part-time 4wd set-up? I wonder what percentage of passenger (not pickup trucks) vehicles are still driven from the rear? Maybe they were afraid of the parasitic loss of work on a ball-and-claw, or birfield? Maybe the engineers broke a cv joint, because the load on a set of leaf springs (axle wrap), combined with intermittent traction climbing thru rocks, must be like an impact hammer on the weaker front drivetrain.
The vehicle's kingpin angle - defined by the ball joints, wheel centers, etc. will be engineered so that it can keep the vehicle tracking straight (yes, properly tuned, an _J40 you can just let go of the steering wheel - steering slop from the factory is not undesirable if it just drives straight by itself (throttle, cruise, and brake), just like the other vehicles parked in my driveway). However, the price for stable, and mostly rear axle drive, is in the vehicles ability to corner, particularly with bumps in the road. Makes me wonder why we push our 4wd vehicles and not pull them?
Notice how many basically rwd, lifted, bigger-tires, vehicles are on an average Craigslist page - it must be 10x greater than what one observes waiting at an average traffic light. I wonder if hacked up vehicles have more or less average numbers of owners. I can think of two 40s that died from complications relating to SOA. I know that my first 40 met a fate of plasma cutter, after I sold it - the only thing still living is the roll cage. Rear-wheel-drive is a horrible way to shrink a map.