I'm told by the shop manual that the torque tube for the std trans Buicks (1940 -1952) is matched to the differential gear carrier and that I shouldn't even separate them. Why would that be? I want to swap a taller gear set into another axle for the same year car. To do that I want to keep the matched pinion and gear set in the carrier but swap the axle housing and torque tube. What trouble is the shop manual trying to keep me from? This is a 1940 Buick with the 320 cu in engine.