i wanted to no if this was an easy fix or if i would need to take it to the shop
Take it to a shop. In order to replace an axle seal on the rear axle, the axle shafts have to be removed which requires removing the brakes, draining the dif fluid and disassembaling the differential. Disassembly requires removing the c-clip and possible the carrier and shims. Once you reassemble the axle, you'll have to reset the backlash of the differential (tension between the ring gear and the pinion) and this requires a dial indicator. You'll need working knowledge of the inner workings of your axle before you tear into it. If this is on a front whell drive axle assembly, you're really screwed. The best thing to do is take it to a driveline shop that specializes in import vehicles, front wheel/all wheel drive, and independent suspensions.
It's best to replace the axle. Dirt can get into the axle and damage it and furthermore it's been running without grease. Your taking everything apart so why not put a new axle in there. Replacing an front axle shaft on a Subaru is one of the easiest of cars to do. It took about 25 min to replace the left front axle on my '96 Subaru Legacy AWD wagon. The differential does not need to be disassembled/drained contrary to what the above poster wrote. However bring it to a garage if you don't feel comfortable taking your front end apart or don't have the right tools. Keep in mind many garages around the country are not that familiar with Subaru's unless if you live here in the northeast so you may be overcharged.
