2002 z66 Rear Diff Change (Basic questions)

As the title says, my 2002 z66 needs its rear diff fluid changed...I've got a pretty decent leak occurring as pictured.  In looking at my rear diff, I believe that I see a drain plug on mine, any reason I need to take the cover off then?

The Leak..assuming that's a Magnetic plug that oil is leaking from?




Drain plug?




Fill plug:

Nope no need, but where is it leaking from

There's a plug in the rear diff cover (blocked by the ?sway bar?).  My plan was to drain the oil, take that off, and use a little loctite to seal it up?  On the farm, we'd just throw some teflon tape on stuff like this and move on...but trying to keep the old gal on the road...185k miles and going strong...

Cool, be aware the covers have been known to rust thru and not fixable.

MS03 2500 said:

Cool, be aware the covers have been known to rust thru and not fixable.

Click to expand...

Thanks, yes, I had read that (probably here) a while ago.  Turns out the leak was from the rear magnetic plug.  I find it odd that mine has 2 fill locations, the front of the diff & the cover.  Regardless, the leak turned out a pretty loose rear fill plug.  A little loctite on the threads and snugged it up good this time.

Changed the oil out for Mobil-1 75w-90 Full Synthetic as required and we're all snugged up and leak free.  Another maintenance item complete...now its time to start getting after the rust...I know I can't stop it, but I can sure try to slow it down some.

pull the cover for a complete clean.
mine 2003 has a magnet inside attached to cover that needs cleaned off

My last Avalanche was a 2003 Z66, the rear diff was low on fluid everytime I checked it, even the original glovebox owners manual stated it needed to be checked every 15,000 miles and every 15,000 it was low. Hope my 2013 Avalanche rear diff stays full, but I'll still check it