Employee was working on rebuilding a planetary. The planetary had 3 gears that were presumed stuck, a pry bar was used to free the first 2 gears. On the 3rd gear the employee was showing the shop planner that the gear was stuck. EE gently wiggled the 3rd gear & unexpectedly it freed up causing EE's finger to pinch in the housing. EE was wearing a latex mechanic glove.