Broke a 4L80e mounting ear

[Daveo91Burb]

Gotta come clean here - I'm an idiot. The dowel pins are missing, so they weren't able to help get engine and tranny lined up. pretty sure that's the whole cause of this mess. I didn't realize my screw up till after the first post. And not sure how I missed them. Possibly because I switched machinists in the middle of my engine build. I don't remember having to install those pins in the block when I had my vette's engine machined, I think I brought it home with them already in. But they're definitely not in this block. And I'm not even sure where they are, I looked through boxes of parts the other night, probably still in one of the two machine shops. New ones on order.

Tranny is coming out this weekend and I'll assess then. I'll post pics of the cracked ear when I get it out. I think the point of the JB weld is not that it will serve as any kind of load carrying mechanism, it's just to keep the bell housing intact. Everyone seems to agree that five bolts (assuming the pins are installed) will be just fine. But.........I work for an electric utility and although I am not an aluminum welder I know several since our substations are full of aluminum bus work and there are a lot of welded connections. One of those guys is a car guy and he's helped me with other "projects" like this in the past. (He has his own equipment at home of course). If he's interested I may get that bell TIG welded yet. We'll see.

Thanks for all the help.

 

[shiftpro]

Gotta come clean here - I'm an idiot. The dowel pins are missing, so they weren't able to help get engine and tranny lined up. pretty sure that's the whole cause of this mess. I didn't realize my screw up till after the first post. And not sure how I missed them. Possibly because I switched machinists in the middle of my engine build. I don't remember having to install those pins in the block when I had my vette's engine machined, I think I brought it home with them already in. But they're definitely not in this block. And I'm not even sure where they are, I looked through boxes of parts the other night, probably still in one of the two machine shops. New ones on order.

Tranny is coming out this weekend and I'll assess then. I'll post pics of the cracked ear when I get it out. I think the point of the JB weld is not that it will serve as any kind of load carrying mechanism, it's just to keep the bell housing intact. Everyone seems to agree that five bolts (assuming the pins are installed) will be just fine. But.........I work for an electric utility and although I am not an aluminum welder I know several since our substations are full of aluminum bus work and there are a lot of welded connections. One of those guys is a car guy and he's helped me with other "projects" like this in the past. (He has his own equipment at home of course). If he's interested I may get that bell TIG welded yet. We'll see.

Thanks for all the help.

Yes you are absolutely an idiot. I mean after all, you make a living rebuilding engines and doing R&R being a professional mechanic so what's your excuse?
You realize I am kidding and the mistake you made is completely understandable.

I want to comment on the JB weld... well if you did JB glue the stinker... it will never be properly repaired(tig) down the road. The JB would have to be completely ground away because even a spec will cause the tig weld to **** it's self. Big gaps with aluminum wire feed are not a problem but you would need a jig or... best another block to bolt the housing and broken piece to before welding. Come to think of it, should do this anyway no matter how it's welded.
And it doesn't have to be tig welded, aluminum wire feed would suffice.

 

[bucket]

It all makes sense now. At least you know what caused it to break and you won't have to worry about it in the next go around.

And I agree, if the trans is back out, then it would be best to have it welded back up.

 

[idahovette]

I'd go back to the machinist and ask for the for the dowels and tell that he really screwed you up. Probably won't do any good but let em know!!!

 

[Daveo91Burb]

I'd go back to the machinist and ask for the for the dowels and tell that he really screwed you up. Probably won't do any good but let em know!!!

All joking aside I might have to do that. Having a helluva time finding the stock length pins. These ones came in the mail today, thought they were regular length but they say “extra long”. Racing style for with a motor plate? I’m guessing they’d be too long?

There must be something I’m missing or I’m searching the wrong term. If anyone knows where to get stock length bell housing dowel pins let me know.

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[idahovette]

Check them in your transmission to make sure they fit the holes and maybe use them anyway, a little extra length might not hurt??

 

[shiftpro]

Check them in your transmission to make sure they fit the holes and maybe use them anyway, a little extra length might not hurt??

Oh yeah ask my girlfriend about that...

 

[idahovette]

Oh yeah ask my girlfriend about that...

Kinda fell into that one, uh maybe NOT a good choice of words here either!!

 

[hoagster]

Now I'm not an expert, but researching for an LS swap, only 5 bolts are used for the bell housing. I would think the engineers would have used 6 if it was necessary

 

[Daveo91Burb]

Got the tranny out today. Here are better pics of the break. The thing that makes me nervous is how close the break is to the dowel pin hole? Change anyone’s mind about whether or not to get it welded? How difficult a weld is that going to be for a good welder?

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[Frankenchevy]

Dang, I would’ve never guessed the cast aluminum to be that brittle.

Sorry, I’m of no help..

 

[HotRodPC]

I wish I could get pics of the JB Weld repair on mine, but I'm 99% certain, that's the transmission that's in my truck. I know some disagree but I'd have no problem whatsoever JB Welding that into place. That is very similar to my break, mine might be a little bigger. Appears to me you do still have some meat around the dowl pin hole. If it's not a hot rod race truck, I'd JB weld it and SEND IT !!!

How I did mine, I did not sand or file the case on the crack at all. I sprayed with some Brake Cleaner on both pieces to make sure it was good and clean and let that dry for about 5 minutes and don't touch it with anything. Then I used a stick and applied the mixed up JB Weld on the broken piece. Probably an amount like half of what you'd put on your toothbrush of toothpaste. Then pushed it into place and let it squeeze out on both sides and just left it alone without wiping anything away. So now the crack is filled in on both sides with a little bead on both sides. I let it dry for about 24 hours before I even touched it. Next day I was a little rough with it, pushing and pulling on it and it was solid. I got a big screwdriver with a good size handle on it and tapped and banged on the broken piece and it didn't budge an inth of a hair.

I'm sure it's not as strong as original or tig welded in, but it's strong enough and I'm not worried about losing that piece and I know there's no open hole in the bellhousing where a nut, bolt or other junk can fall down in there on top of the spinning torque converter.

 

[bucket]

I'd still have someone weld it up. Looks easy to do.

Actually, that's a bit of a lie. I'd probably buy some aluminum wire for my mig welder and give it a whirl.

 

[crpntr78]

Any welder worth his salt should have no problem with that. It being a good clean break like that.

 

[Daveo91Burb]

yeah going to have to think about this one and talk to guys at work tomorrow see what they think (and see if one of em can do it for me or give me a good place to go). In a perfect world I’d definitely get it welded but that means loading into the back of the wife’s minivan, driving it somewhere, etc. And I think 99% chance that @HotRodPC is right and it won’t be an issue. But if I can find a good welding option that’s the way I’ll go - I just know I’m not that right option!

The good news I found when I dropped tranny: it’s a GM service replacement so at least it’s somewhat less miles than the truck (250k+). I had zero issues with tranny before I pulled engine, BTW. Ran awesome.

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