Magnetic drain plugs are good
Basic drain plugs are fine too, The diff doesn't have as many moving parts as a engine or transmission does, plus the oil is a lot thicker. Not many little shavings are present. Just wait until you change your diff oil, it moves like syrup and smells horrid.
Changing Diff Oil
Step 1. Buy synthetic diff oil, it lasts a lot longer than conventional make sure you buy the right weight too, mine was a 3.73 LSD and the oil was 75W-140 I Think I also required 4oz friction modifier for the LS
Step 2. Loosen up all the bolts around the diff cover, take all but top ones out, leaves the top ones loose
Step 3. Carefully, pry on the bottom of the cover. This allows the oil to drain out the bottom slowly, have a pan ready to catch the oil
Step 4. Spray cleaner into diff and wipe down everything you can see, this is a good time to inspect your pinion gears, moderate wear is expected
Step 5. Remove old gasket, using a razor blade or scraper, you should get all the old gasket off, then take a wire brush or small sand paper and lightly brush until you see shiny metal on the diff housing. This will allow the silicone something to grab onto as well.
Step 6. Since you have a new cover spray it down with cleaner, even though its nice and new cleaner always helps
Step 7. Clean up all the old bolts, by either wire brush or just wipe them down your choice
Step 8. Make sure all components are around you and ready for reassembly, ie Bolts, Cover, SIlicone
Step 9. Take cover and align it to the housing, this will show you the right orientation
Step 10. Make sure the surfaces are dry and ready for silicone
Step 11. Get your silicone ready to use, start your bead at one end of the cover it should be at least 1/4" width, make sure you go UNDERNEATH each bolt as in a U shape. Try to make it around the cover with out stopping the bead, this makes sure you don't get any gaps. If you do stop, don't start at the end of the bead go over a portion where you stopped.
-Don't wait to long to apply the silicone because it starts to cure as it hits the air, but don't rush either, take your time and do it right
-the reason you go underneath the bolt whole is because the if you go above then the oil might seep around the bolt and will leak through the holes, going underneath allows it to seal the oil within the cover entirely
Step 12. Having a few bolts in one hand, place your cover back on to the housing make sure its faced the right way, then screw a few bolts into the housing to hold the cover on.
Step 13. Finger tighten all the bolts around the diff, then using your ratchet tighten the bolts in a criss cross pattern, this allows for equal pressure around the cover rather than just one end.
Step 14. Once all bolts are tight wait until the silicone is dry, DO NOT ADD OIL right after you put your cover on, this may weaken the silicone. Odds are some silicone should have oozed out the sides, wait until that is dry, then wait 5 more mins.
Step 15. Add oil. If your new cover comes with a fill hole add it there until it pours out, If not pour the diff fluid from behind the differential, you will see the drain plug from the back of the diff. If you have a LS then you need to add 4 oz of friction modifier as well or you will toast your shims.
Step 16. Replace fill plug
Step 17. Take it for a drive. Park and check for leaks
Step 18. Get a beer your done!
Sorry for all the detail, but better to know how to do it right then be sorry in the wrong run
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