hey guys im running a 3rd gen aluminum drive shaft in a 97 WS6. when i first installed the shaft i notice the u joints where to small and had allot of play when i tighten the bolts to the axle. so i just took off the caps that came with it and installed the caps from my factory steel drive shaft and it bolted up. i was having some weird noise/vibration when accelerating from a stop. then it goes away as i pick up more speed. took it to school and my teacher said that its unsafe and to use the proper u joint or the car could flip over. im doing a 800 mile trip tomorrow so please anyone know the proper u joint or at least a part number? i went to the parts store and had no luck. thanks for the help guys.