possible a piece of trash has gotten into a bearing race or in the input shaft assembly. Trash can accumulate in the galleys cast into the side of the transmission case. Those galleys feed thrown off oil to the input shaft assembly, the carrier, bull pinion and reverse idler bearings. Perhaps the rough road shook something loose.
If the front bearing is loose on the input shaft then the back one is too. Those two on the input shaft plus the main shaft pilot bearing and main shaft rear bearing work together as a system. The front three are pretty close coupled so consider replacing at least the front three as a set.