How do the rollers on the side bearings look? Usually the hardness comes off in flakes sticking to the magnet. As the bearings wear, they get thinner taking up side bearing preload (the shims have to be forced in slightly to put pressure on the side bearings). When the preload is gone the carrier can move side to side. Who did the previous install? It would be nice to know how much preload was put on the side bearings with shims. I can tell it's been into as the factory puts one large cast iron spacer and one shim per side, service procedure has you put a steel spacer and multiple shims to take up the extra space and add preload. I reuse the cast iron spacers anyway 'cause it's a hassle to stack up a bunch of steels but they are brittle being cast iron and will crack if hammered in improperly.