Time to MIG weld a bolt into the plug, then you can get some purchase or a rattle gun on it..

 

Be sure to remove, or at least loosen, the fill plug before you remove the drain. You also should NOT be using an "extension", that is going to be a part of your problem - the plug takes a 10mm square drive, a 3/8" square drive extension is not only undersized. it has rounded corners.

As Phil has suggested mig or arc weld a bolt into it and then back it out.

 

Oh my... I wish I would have known that before now. I just assumed I was doing it correctly because it fit. Ergh here's hoping I haven't messed it up royally! I'll purchase one of those 10mm square drives and pray.

 

Just for the future - everything in this car is metric. And follow Fordem’s advice above - make sure you can get the fill plug out before removing the drain plug.

 

Roger that. Anyone know where I can find a replacement plug?

 

If you weld the bolt onto the present one, you may reuse it.

 

Please put the specs of your vehicle (year, engine, etc.) into your signature, so that people know what you’re driving. If you insist on getting a new plug, the part number is 09246-16010

 

Gotcha, done. Now that you know my vehicle is a 1994 Geo Tracker, is that still the correct part number?

Wouldn't it be wise to get a new plug considering how much damage I've done to this one, or is there a downside to a new plug?

 

Don't go to "extremes" first. Try the KISS principle. First, make sure you have the correct tool -- exact socket size, and as mentioned above as short a socket as possible. If a foot long socket wrench won't budge it, make sure you are trying to turn it COUNTER-clockwise. Then try a longer wrench.

I had to replace my shocks a couple of months ago which had 20 year old rusted bolts. All the Liquid Wrench and heat in the world would not move the nuts with an 18" wrench, but a 28" wrench gave me the extra leverage it needed.

 

You’ve only done damage to the square socket area, not the actual threads. Aqua’s suggestion is a good one, if you know how to weld the bolt on to the existing plug. If you can’t, then get the new plug. The part number is the same for all Trackicks.

 

I've been running my GV with a bolt welded into the fill plug for a couple of years now - since yours is the drain plug just make sure to keep the bolt short so that it doesn't project too far down, or swap the drain & fill plugs when you have them out - the fill plug is at the side so a projecting bolt will not strike anything as you drive.

 

Wonderful, thank you all for the sound advice.

 

Just a follow up for anyone who may find this post. I had to take it into the shop to replace the CAT and the awesome mechanic there welding a nut onto the plug for me. All is well now, fresh fluid feeling good!