Yuppers, a trans, T-case, driveshafts, and front axle, plus the shifter stuff.
A J Truck will not compete with an MJ offroad, nor will it ride as nice or get good fuel economy--I know this from experience. For a high schooler, there isn't much reason to get a fullsize truck, especially considering that a properly equipped MJ (Metric Ton truck) had the same towing capacity as a J10.