Go to Harbor Freight and get a socket that fits (22mm?) then weld it onto the drain plug, the heat should break the bond. Get a new drain plug before doing anything first though!

I managed to get about 93oz of the old fluid out from the fill hole using a pump. Refilled with new oil and put a new washer and new plug on the fill hole. Drain plug isn’t going to be able to come off without drilling it out all the way. Getting the drain plug to turn isn’t an issue, it just doesn’t unthread.

At this point, I’m just going to monitor the drain plug for leaks.

I’ll probably get an m18 O2 bung and weld it into the factory location the next time I need to change the oil. I can weld on a flange to the bung and then reverse mount it to the rear diff so the threads are inside and not sticking out of the housing. Would end up good as new.

Another use for the O2 sensor tap - if you have a Kohler single-knob shower head and the cartridge valve is so stuck the front half breaks off, drill whats left of the cartridge slightly smaller than the tap, thread in the tap and use it to extract the old cartridge...I probably saved a few hundred bucks not calling in a plumber LOL

Mine has been stuck, stripped beyond rescue since the day I bought it.

I didn't care then, or now.

You can fill through the breather vent valve. It's located towards the top drivers side of the pumpkin.

Look up your gear oil capacity and put that much in. If you go a bit over, it'll just come out the breather valve. No harm.

Side note; the breather valve probably needs to be replaced anyways and they cost about $15.


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His issue is with the rear drain plug which normally doesn't have this problem.

Why would you fill thru the breather valve? That would take forever. Why not just use the fill plug unless you stripped that too? And if so, why wouldn't you weld a nut or bolt or sacrificial allen key to it to get it out and replace it with a new one?

Filling thru the breather valve would also likely cause you to over fill it since it sits at the top of the diff. The diff shouldn't hold that much oil. That's why the fill plug is only about 3/4 of the way up, if that.

This was the drain plug from my front diff.

I ended up having to JB weld mine shut . All the wrenching I'd done on the drain bolt to try and remove it caused a leak to start. I got the steel reinforced two-part kind and filled the whole area and then capped it off with a solid washer. I taped the whole thing down for everything to set, and it's solid now. Tacky and embarrassing, but solid.

I pulled off the tape, cleaned up all the adhesive, sanded everything smooth, and sprayed some ZRC then high temp flat black to match the factory paint. Only a person working under my car would be able to spot the "repair."

I hate the fix, but at this point, I'm actively saving for full rebuild or a new axle. Not ~just~ because of this, but it's definitely a tipping point. I've got at least 30,000 miles to save up for it.

Do you have a picture of how the repair turned out? and maybe of the bolt?

Just curious is all.

Nice job on fixing it!

I can take one this evening. Not much to "see" since it's all covered up, but I'll be down there anyway tonight to check on everything so it's no big deal to take a few shots while I'm there.

I need to smooth out the cap a little more and go over with another coat of paint, but there she is in all her tacky glory.

Everything behind that cap is filled solid with JB Weld. (Something something rural Georgia.)

FWIW, I change the gear oil in my T4R diffs every 30k miles (tow a boat). The first time getting the drain plug out is the hardest (factory tight), or at least it should be. Each time I do a change, I put anti-seize around the outside edge of the hole on the diff and also around the inside of the washer on the plug before reinstalling it. That helps a lot to resist rust, but the important thing is to torque it to spec (36 ft lbs on rear diff) and no tighter!!! Makes the job a lot easier going forward. Sorry to jump in like this, but thought it might help.

I did the rear drain plug on my 2005 4runner rear differential a few years ago. It was about the easiest job I ever did on the 4runner.

Just loosen both drain and fill plugs on the rear differential, drain the 3 old quarts of Valvoline lube, then refill with 3 quarts of new Valvoline lube 75W-90 - until it comes out the fill hole. DONE:

Took 15 minutes. No jack stands, just a socket wrench. I didn't use synthetic. I'll do it again with new Vavoline 90W in five to seven years.

I did mine at 140,000 miles, and the old lube oil was black (but looked good / new / amber color with the black). I'll do it again in 75,000 miles. You need a long handle ratchet, as the bolts are in there tight!

Two wheel drives don't have a front differential, so don't bother looking for one.

My feeling is that most people never change the differential fluids - ever! YouTube

The rear differential gear oil should be changed. You can lose a rear differential by never changing the gear oil.

I reused the old washers.

I think he already knows how to do the job based on the posts. Only issue was the disorientation caused by being upside down

I think the fact that he made this post about changing the diff fluid is indication that he knows the fluid should be changed. Earlier he mentioned that even though the drain was stuck, he was able to pump 93 oz out. I think put a bit over 3 qts in when I changed mine, so to it looks like he got most of it out.