1997 Ford Explorer snap ring

My 44-05 transfer case failed on me, the shift fork broke and I replaced it and noticed the snap ring (7917) that holds the thrust bearing (7D221) down to the cam and coil housing assembly (7g362) on the rear output shaft has disintegrated, no one at ford can tell me what snap ring I need and all I have is the part numbers in the workshop manual to go by which I have included, I am also including a picture of where the snap ring goes, there is an arrow pointing to the groove it sits in, any assistance would be appreciated