i just bought an 03 regular cab 1500 shortbed and have taken it off roading for the first time a few days ago. whenever my tires dug into the dirt or sand a lil the entire rear of the truck would shake pretty bad. the whole bed was goin crazy. and the fourwheel shifter on the floor was bobbing back and forth pretty fast. is this normal for offroading or do i have a bad diff or sumpthing.

any opinions or info about my truck please leave it also how do you trucks react to dry soft dirt