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Weird Differential leak please read

bartamos

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1980 12bolt leaking at what looks like plug welds or ? Lower rear, near where axle tube goes into housing. there are about four of these "plugs". How do I plug this leak. Anybody ever had this? I never have seen this before. Just cleaned painted, sealed and filled unit. Damn it! Are these holes for casting purposes or to weld tube to housing? How are they sealed at factory? These are round, smooth, slightly raised, 3/4 diameter spots about 4-6 places. Only one leaks. thanks.
 
Never seen it on a 12 bolt, but I have seen it on almost every D44 Hi Pinion that I have worked on.

Weld it better
 
Thanks, I really didn't know if they were welds or not.
 
resurrected_jimmy said:
gear oil is cheap, I just left mine alone

Same as I did with my 12-bolt leaking in the same place. Cast iron is a pain in the ass to weld.
 
Maybe I will weld it with a JB welder. It's unbelievable that it would leak there at a factory plug weld. I can't stand leaks.
 
JB ain't gonna cut it.

My dad welded up my friend's 12 bolt (tubes and plugs I believe) solid with his arc, lasted maybe a week, as if the tubes are twisting. (again)
 
If he welded a bead around where the tube meets housing, it ain't going to twist from that point inward, which is where the plugs are. Maybe I'm not getting your meaning? Anyway you know I'm not having a twisting/movement problem, just a leak. With very little pressure (as long as the vent is open) I think anything that will stick to the casting should work. No rock climbing or hard torqueing here. Correctum me if I'm wrong.
 
It just leaks. Plug welds were visibly cracked, meaning the tubes are trying to move, so welded it up again, and more leaks.

I guess if it's just seeping out you can try silicone, but how would you clean all the oil out of the porous cast iron so it actually gets good adhesion? Maybe propane or something.

My opinion though is that if it starts to leak, the tubes are moving, or it would have leaked from the get-go.
 
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I got it from a donor 80's suburban to put under my 56 GMC suburban (actually called a carryall) I'm building as a 4X4. Maybe when I run it (still building it with body off) the oil will run down the tubes some. This plug weld is at the "top" of the oil level. Maybe then it will be "above" the level and stop leaking. I hope, I hope. As my Mom used to say "hope in one hand and $h!t in the other and see which one fills up first. Anyway, a few left and right donuts should do it when I get finished with it. (4 yrs and counting). If not I will arc weld it which will blast thru oil, paint or any other impurities and should seal it. Too hot to climb under it and do that yet. Like you said oil is cheap and so is a drip pan for now. I just wanted to know if anyone has had this and looks like it's not just me.
 

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