I recently bought a 1995 Tracker.  When I bought it, it need some obvious tlc.  As part of the maintaince to it I decided to change ALL fluids.  Well when I came to the transfer case the top (filler) plug is so far rounded off a 3/8" ratchet makes no contact.  Before anyone asks, no I did not do take the bottom plug out first so it is still filled with fluid.  However, for peace of mind by judging how bad the diff fluid was, I would like to change this also.  Any ideas how to get it out?

Drill in the center with a 3/8 or so drill bit, and use an easy
out in the hole to extract the old damaged plug. You will
need to use some grease on the drill bit to hold the metal
chips so they don't go into the case

Wild

I have been there on a nissan,I found a large square easyout that I drove in the plug without drilling.  It was tapered and I ground it off till I got it the size that would fit tight.  Good luck. c

Good Call, I didn't think about the square easy outs, just the spiral ones,
I like that better as drilling could be a real PITA under the truck

Wild

Weld a nut onto the plug.  The heat from the welding will help break the plug loose.  Then just put a socket on the nut and the plug will probably come right out.

I realise that it was probably rounded off by a previous owner, but, since you mentioned that a 3/8 ratchet made no contact, I though you might like to know that a 3/8 square drive is not the correct tool.

It needs a 10 mm square drive.

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Good point, but the plugs get rounded off from over zealous
mechanics on the install, they don't need to be that tight to
stay put, and they don't get rounded out on the removal either

The difference is quite small so the 3/8 ratchet works fine, just
don't torque it to 500 ft Lbs and it will be fine

Wild

3/8" is like .5mm smaller than 10mm.  So if a 3/8" square drive won't touch it, neither will a 10mm.

Don't ya just love these mechanics that install every part with an impact?

Don't ya just love these mechanics that install every part with an impact?

An air impact works good for taking the plugs out too.  I have had some that were going to strip the square hole, if I would have tried to use a breaker bar.  But the impact zipped them right out without damaging the square drive.