Some units have small freeze plugs and your may or may not. But if it's the shaft end (seems small in the photo for a shaft and is why I think it's likely a freeze plug) then it's the idler gear that is in contact with the trans gear. The drive gear or power shaft gear as it were shifts on/off of that shaft. No matter what just go to a Power Drive Spicer/Chelsea distributor or good Truck Equipment house and get what you need. Take the tag info with you if you have it. Not wanting to remove it means not repairing it.
