I Streipped The Rear Diff Fill Plug. Now What?

uh6077 · July 19, 2007

I drained the rear diff fluid in my 99 NBS. When it was totally empty I tried to get the the fill plug off but it would not budge. After lots of time with a long extension, torch, PB Blaster and a hammer.... still nothing. Eventually the plug stripped out . So now I have an empty diff with no way to fill it. I have a new gasket on hand if I need to take the cover off. Is it possible to drill and tap a fill plug into the cover? Any ideas what I should try next. I have some easy outs but I really don't think they would budge the bolt. I had all my strength on the end of a 2ft bar and it still did not budge. I had it red hot with the torch.. nothing. Just when I had a victory with the bad fuel injector then this happens. I hate that I am not willing to let anyone else work on my vehicles.

AFD256 · July 19, 2007

That sucks, you don't think if you soak it repeatly with PB-than use a bolt extractor that it would work? Maybe tapping it with a hammer? I saw this stuff at autozone claimed it froze the rusty bolt to loosen it . If a ll else fails burn the entire truck and get a new one. Wait don't do the last thing might be a tad illegal

99silverado1500 · July 19, 2007

could pb blast soak the threads and then jb weld a socket in and try that maybe?

leboyd · July 19, 2007

It might weaken the cover.

Using the JB weld idea, have you thought about JBing another bolt head on the old one? I had a situation where I did this and it worked.

Once you do this, you might use an impact wrench.

asilverblazer · July 19, 2007

How bout stick/battery weld an extension to the plug?

uh6077 · July 19, 2007

I hadn't thought about welding onto the plug. I have a 225 arc welder so it shouldn't be a problem as long as the leads will reach. It sucks because the plug is flush and only has a square inset that takes a 3/8in socket wrench... with no socket.

saltwater_addict · July 19, 2007

weld an extension (short) jb weld probable isnt gonna help if its really stripped

99silverado1500 · July 19, 2007

well, you could always go to harbor freight or walmart and get a 3 dollar 3/8" socket, and jb weld or even weld it in. It has to come out somehow.

uh6077 · July 19, 2007

It is not a bolt though, it is a plug. It just a has a 3/8in square hole there. You stick your socket wrench in the hole just like if you were putting a socket on the wrench. It is a horrible design. Who the hell though a little square hole would be strong enough to do anything with. Plus it is only like 1/4in deep so you can not even stick the whole wrench in it, just the tip. I am an engineer but sometimes I just shake my head at what other engineers some up with.

carneyman · July 19, 2007

It is not a bolt though, it is a plug. It just a has a 3/8in square hole there. You stick your socket wrench in the hole just like if you were putting a socket on the wrench. It is a horrible design. Who the hell though a little square hole would be strong enough to do anything with. Plus it is only like 1/4in deep so you can not even stick the whole wrench in it, just the tip. I am an engineer but sometimes I just shake my head at what other engineers some up with.

I agree. I look at some things and know a monkey could do better designing them.

Be careful if you weld it. Don't wanna weld the plug in.

saltwater_addict · July 19, 2007

Ive never had a problem with them but i could see how it would be easy. If its the plug on the bottom, it helps to put a bottle jack with pressure under your ratchet. worked like a charm for my transmission plug that everyone seems to have so much trouble with.