You won't damage the box, it is designed to turn under a lot of pressure and torque. (Feedback from the tires!) Just get a piece of leather or heavy fabric and put a pair of vise grips on the top shaft with the leather/fabric between the shaft and the vise grips. You won't need to put hardly any pressure on the shaft, it should rotate very easily.
5R08A, "298"(+.060, 6,000+ rpm), T-10, FITech FI, Crane XR-i, Front Disc , Heim Jointed Struts, Spherical Bearing LCAs, Roller Perches, Arning Drop, 1" & 3/4" Anti-Sway Bars, Export & Monte Carlo, and GW Subframes.
Victory Red, Hood Scoop, Eagle 192 Wheels, Power Antenna, White Int. w/ Black trim, Right & *Left* Indicators, Tachometer, Cruise Control, Factory Style Luggage Rack, and a Glass Rear Window.