I just did this job. The "S" spring must first be removed. I managed to lever mine out. To reinstall you need a vise and a pair of needle-nose vise grips to make the job easier.
Once the "S" spring is out, the procedure to remove the "C" clips is the same as for the open rear diff. Remove the 8mm bolt that holds the pin in, remove the pin and push the axles in to access the "C" clips. Use a magnet to remove them from the axle.
Be careful to not round the head on the 8mm bolt that holds the pin in, or you're screwed. I found a youtube video that showed how to get the "S" clip back in again.
The axles have an O-ring that cushions the "C" clips. If you don't have these in place the diff will tend to make noise when going around corners. If you need new O-rings, you can pick them up at any hardware store. There's nothing special about them.