3340 brake job

doing a brake job, after removing both rear diff i noticed on the left side inside the gearbox..where the diff shaft goes into the transmission I noticed what looks like a gear that goes around the shaft, then the shaft goes farther in the transmission. There is not one on the right side.. not sure what this is I know it goes on the shaft, but what is it's purpose? it's loose, just sitting in the gear oil, free turning and moves around.. stumped

Hi
you have found the difflock. The parts that you did remove is the akselportals, the diff is in the senter part.
Bjarne

ahha yes after doing more research i realized its the diff lock. now when aligning it when reassembling what does it allign with? do the teeth align with the slots on the inner gear?

The difflock collar must be aligned by hand and held in place by spring force, untill you slip the shaft on