Check endplay with a feeler gauge between the snap ring and selective washer. .005-.010" is ideal here. Take the time to get it right.
You are now ready to disassemble the rear section and install it in the case.
Disassemble it to the rear planetary. Set the output shaft, rear ring gear, and rear carrier assembly in the case. Position the output shaft using the tool or other means so that the ring gear lugs line up with the parking pawl.