Messed up rear differential cover change

[Cuckfield]

Hello fellas, dropped the cover on my 14 bolt 10.5 ring gear, drained the fluid, cleaned the magnet, and bought a new cover.

But silly me, I used the paper gasket that came with it, and as i was putting the cover and new gasket on the bottom bolt on the differential cover was really difficult to turn in. Despite trying every which way to thread it on straight I couldn't get it to go on easy, so I stupidly cranked it on with a breaker bar, in hindsight likely crossthreading it.
Now that exact bolt on the very bottom is verrrrrry slowly weeping gear oil.

How can I fix this? Obviously I messed up the bolt threading. But it should have sealed up pretty well regardless, right? Should I have used rtv instead of a paper gasket? Honestly I'm lost.

Does anyone know how i can reinstall the cover without shredding that bottom bolt any further, and ensuring everything doesn't leak?

 

[b454rat]

Pull it and run a tap thru it

 

[GoToGuy]

I am trying to understand how one would continue with the" bigger hammer theory " , when it's obvious that something is not normal.
You've obviously trashed the machine threads in the diff case. As in two thread paths now. So most likely the case cover, bolt, case threads can no longer seal as designed.
Depending on how trashed it is, I would first consider a helicoil, or a flush mounting steel rivnut. And a new bolt.
Think finesse, not gorilla .

 

[Cuckfield]

I am trying to understand how one would continue with the" bigger hammer theory " , when it's obvious that something is not normal.
You've obviously trashed the machine threads in the diff case. As in two thread paths now. So most likely the case cover, bolt, case threads can no longer seal as designed.
Depending on how trashed it is, I would first consider a helicoil, or a flush mounting steel rivnut. And a new bolt.
Think finesse, not gorilla .

Yeah, profoundly dumb, I know. I should have just taken it off and started again threading that one first.

I should be able to find a new bolt at a hardware store by taking one of the non trashed bolts in and testing it on one of those thread things they have in the nuts and bolts aisle eh?

How can I install a helicoil? Never done it before.

 

[GoToGuy]

You could try to run tap through it. It might clean up, although since you forced a new thread path it might futile. Worst case is purchase a helicoil kit for that size repair.
Always start with year, make, model, eng. Since you didn't list it, could be sae or metric. Have a friend that knows helicoil repair? First timer should have help or supervision. Utube instruction, maybe helpful. Good luck!

 

[Cuckfield]

You could try to run tap through it. It might clean up, although since you forced a new thread path it might futile. Worst case is purchase a helicoil kit for that size repair.
Always start with year, make, model, eng. Since you didn't list it, could be sae or metric. Have a friend that knows helicoil repair? First timer should have help or supervision. Utube instruction, maybe helpful. Good luck!

Sorry, 1995 chevrolet k2500 7.4l
I'll watch a few videos. Any clues on the size?

 

[GoToGuy]

3/8 x 16, 3/4 length. Grade 5. Check at hardware store .

 

[Cuckfield]

3/8 x 16, 3/4 length. Grade 5. Check at hardware store .

Thank you very much!

 

[GrimsterGMC]

You could try to run tap through it. It might clean up, although since you forced a new thread path it might futile. Worst case is purchase a helicoil kit for that size repair.
Always start with year, make, model, eng. Since you didn't list it, could be sae or metric. Have a friend that knows helicoil repair? First timer should have help or supervision. Utube instruction, maybe helpful. Good luck!

A thread chaser/repairer would be the first option as it doesn't cut any material just pushes the misplaced material back into place. Then if it's too far gone cutting a new thread would be an option.

 

[454cid]

I use paper gaskets just like it was originally equipped with. Last time I got a whole GM kit that was cover, gasket, and bolts.