[suntreemcanic]

The differential on my 66 Chevelle is seeping oil at the plug welds where the axle tubes fit into the differential casting. How can I fix that permanently? This is the original rear end for this car. It is a Kansas City car.

 

[big gear head]

That's very common. Most of them do that. Other than grinding out the welds and doing them over, which isn't easy, there isn't really a fix for it. The welds are nickel.

 

[Lou Merrell]

There's got to be some kind of two part epoxy repair that can be done there. Or a fillet weld?

 

[lucifershammer]

There's got to be some kind of two part epoxy repair that can be done there.

I’ve had succes by cleaning it up really well with a wire wheel and then using JB Weld to cover the plug weld to seal them up, then painting over it.

Have to drain the rear axle first though to keep it from weeping while you are doing the cleanup, unless it is out and you can rotate it around some.

 

[suntreemcanic]

Sense it is common and it is steel welding is the way to go.I have three places it is seeping, not enough to drip on floor but makes a mess on the differential. I can clean it up real well and I will wire brush it and identify the exact location of the seep. If welding doesn't work I can always grind out my repair out and try JB Weld. Thank you for everybody's time.

 

[Hotwire]

Get a can or 2 of red brakleen and hose the area off, I'd also pull the cover/drain the rear, because if gear oil is getting out, brakleen/dirt will get in. Dry with compressed air. Once dry I would get seamsealer and do the best to plug the leaks up, then paint the rear. If applied smoothly you can cover up the seam sealer and not know it was there. The seam sealer is flexible whereas jb weld is not. If you axle tubes move in the slightest the jb weld will do no good.

Mine are leaking the same, I plan on doing the fix above, just not high on the list of to dos.

Also make sure the vent in your axle is completely clean and can do it's job. If any pressure builds up in the rear it will push gear oil out of any where it can.

 

[big gear head]

Sense it is common and it is steel welding is the way to go.I have three places it is seeping, not enough to drip on floor but makes a mess on the differential. I can clean it up real well and I will wire brush it and identify the exact location of the seep. If welding doesn't work I can always grind out my repair out and try JB Weld. Thank you for everybody's time.

It is not steel. It's cast iron. That's why the plug welds are nickel and not steel. You have to treat this as cast iron when welding.