Front diff

I was going to change the front diff fluid today, but I cannot get the fill plug out it just wont give.
I have not touched the drain plug yet so I am still good i made sure i could get the fill plug loose first.
I have tried 3/8 and 1/2 rachet and also a 10 mil hex wrench with pipes for extra leverage
Any thoughts or advice?

 

A hot heat source applied to the plug or try to tighten it first

 

Heat to the housing or freezing the plug using a quick burst of liquid nitrogen or canned air held up side down.

remember heat expands if you heat the plug it will cause the plug to expand you want the plug to separate. I am assuming you sprayed a bunch of PB Blaster or like product. IME Kroil is the best penetrant product but it is not cheap. I would plan on replacing the plug with a quality Stainless Steel plug I think it is a M14-1.5 bolt size if you are not sure replace with an OEM and replace later with a better plug I would suggest a hex head instead of the Allen and don’t over tighten the plug just enough to compress the crush washer I do like to use either anti seize or thread sealant on the threads just a small dab and smear into the threads it will make the next time you have to remove the plug to be drama free

 

When you get it off, maybe replace it with the Lexus version of the front diff plug that's a bolt instead of a hex.
Part Number 90341-24016 (bottom/magnet)
Part Number 90341-18060 (top)

 

Mostly correct, but heating a plug or bolt works better to break the rust free. The heated bolt or plug then cools quickly due to it's small size. That and it will take a significant amount of heat to heat the housing which is bad for it and everything inside of it. Truth is...generally best to weld a nut on stuck plugs because it applies intense heat quickly and they spin right out afterwards. Not easy to do that in this case though.

 

I gave up on it today, I sprayed with PB Blaster, used a wire brush nothing worked the hex head kind of stripped the inside. Just one of those days when nothing worked.

 

It needs hot heat and likely an extractor. Lisle tools 61980 is a good stubby extractor set with large heads to bite on.

 

Some ideas...

Tap inward on the plug with a ball peen hammer and try to remove it if it is not rounded too much.

Get a hardened steel punch and try to make a "pocket" for it on the outer radius of the plug and tap it loose with a hammer and the punch.

Try an extractor. You might have to drill it and hammer the extractor in to get a good bite on it.

If you have a wire feed welder, weld a nut to it.

Heating it will definitely help. A propane torch/MAP gas is probably enough heat. I probably wouldn't use a rose bud or cutting tip on the cast diff housing though.

I removed mine with a hardened punch, propane and a canned air duster can flipped upside down for the freezing effect. It was a pain to access and get a good angle on it. It is a lousy design. A lot of people end up rounding these things out.

 

As suggested, heat, tighten it (it won’t spin, but helps break free), tap the hex key socket in with a mallet to make sure it’s seated.. and they sell this at most Autozones now:



It will break free eventually. You will think you broke your ratchet when it does.

 

This is one of those products that probably 9/10 of us invented in our heads years ago but never capitalized on Canned air too. We could have been rich and retired. I never knew the stuff existed!

 

Right?! I used to chuck a bolt or piece of round rod in the freezer over night, then heat up the offending bolt or nut and quickly touch the frozen bolt to it afterwards. The can is much more convenient...

 

If you get a replacement (preferably the Lexus hex version) in your hand, you can probably drive to a muffler shop and ask them to weld a nut on it and back it out for you in exchange for a case of Modelo.

 

Try putting a ratchet extension on it and bang on the end of it to try to jar it loose.

 

If you can hit it with an air hammer, that might also help.