Auto Parts: 1997 Suburban gear lube change, differential fluid, gear lube

Question
On my 5.7 2WD Suburban, the rear end is making noise and seems to be catching at times.  I do not see a drain plug or fill plug for the differential fluid.  How do I change the fluid, and should I do any other routine maintenance?

Answer
On the right side of the differential you'll find either a 3/8" or 1/2" square socket plug.  Use a ratchet and unscrew the plug.  As long as the vehicle is on level ground - once you remove the plug, if you see fluid running out your differential is full.  If it does not, stick your finger in the hole and feel for the fluid and see how empty it is.

Change the fluid by removing the rear cover to drain, then you can reseal it and fill it through the fill plug hole.  Just fill it up until the fluid runs out of the hole on the side of the differential and install the plug.

When you reseal the differential cover, make sure and let it sit for a few hours (at least) to let the RTV cure somewhat before filling it up.