Pontiac GTO 2004-2006 - differential leak, big deal deal or not?

Just bought a 06 GTO and it has a leak in the differential. It is not dripping but there is a larger area of residue.

Is this common and how easy is it to fix? I am guessing it is a seal or it may be something as easy as the fill plug.

The car has 58k miles.

I would pull the diff. fill plug and clean everything check your fluid level, if you have the money to put down I would buy a Harrop diff. cover for it, it is a pretty nice upgrade.

I agree it kinda looks like the source of that leak is the fill plug ( holding the ID tag on) there.
Hose it down with some carb or brake cleaner and take out the fill plug and check the fluid level and install it again.
When I first did my rear end fluid swap my differential fill plug was all but finger tight, its amazing mine wasnt leaking like yours is.
Also if your differential fluid is dark it might be a good chance to swap in a good quality 85-140 fluid and 2oz of type F friction modifier.
Generally from what I have read many people recommend non-synthetic gear oil for this application as our differentials can be picky with fluid type and friction modifier. It took me a while to find a mix that my differential liked.
hope this helps
--Glenn

I would pull the diff. fill plug and clean everything check your fluid level, if you have the money to put down I would buy a Harrop diff. cover for it, it is a pretty nice upgrade.

Everything said here. Best advice, Harrop's diff cover is really nice and gives you more fluid in the diff to keep it cooler.

Go with Torco gear oil. I haven't had any issues and much cheaper than the dealer.

I had about the same thing a while back, went to change to torco and type F and the plug was just above hand tight, after gear oil change and correct torque no more leaks. Might just put a wrench on it and make sure it is tight.

Just clean the diff off, pull the plug and clean the threads.
Get torco rgo and some type f modifier.
Then put some thread paste/sealant on and reinstall.

Dont waste $500 on a cool diff cover that doesnt do anything.

just clean the diff off, pull the plug and clean the threads.
Get torco rgo and some type f modifier.
Then put some thread paste/sealant on and reinstall.

Dont waste $500 on a cool diff cover that doesnt do anything.

but it looks cool!