Rear axle seal replacement

Okay, this the situation: I went and checked a customer's car out, I got in the passenger seat and noticed a sound when the rear wheel is slowly turning it didn't sound like the wheel bearing itself. So she parked it I jacked it up and took the rear drum cover off on the passenger side and noticed a lot of gear grease was coming from the middle area. In my head I am thinking the seal may just need to be replaced, at the same time I am thinking about changing the bearing too. I don't have access to any press equipment, but I am confident I can change the seal and see if that solves that problem. I just wanted some advice on removing the rear axle on this particular model because I was told I don't have to take the differential cover off just use a slide hammer. Let me know what is the proper procedure. Thanks