Yes, 4.0 w/ class 3 tow package has stiffer/ longer leaf springs. Plus it has a transmission cooler. The more heavy your vehicle is, the more you can tow. I'm a 2wd and tried to rent a 2 axle Uhaul trailer one time. But they wouldn't let me, they said if i had 4wd i could rent it. Just more weight, so that the load can't push you around as much. Plus the 4.0 can tow more than the 3.0, and 3.0 more than the 4 banger because the bigger engine has more Torque/ HP.

 

oh ok i was just wondering thanks