Putting too much weight towards the rear may cause all of these EXCEPT:

Poor weight balance can make vehicle handling unsafe. Too much weight on the steering axle can cause hard steering and damage the steering axle and tires. Underloaded front axles (caused by shifting weight too far to the rear) can make the steering axle weight too light to steer safely. Too little weight on the driving axles can cause poor traction. The drive wheels may spin easily. During bad weather, the truck may not be able to keep going.