Cracked Ear on Engine for Top Bellhousing Bolt

[ElectricWizard]

I had my transmission out in order to fix some leaks, and upon reinstalling it while torquing up the top-driver side bellhousing bolt, one of the E12 ones, the ear on the engine it threads to cracked clean off the block.

The previous owner at some point had replaced the E12 bolts with regular hex bolts, and it seems the ones they replaced it with were too long. I replaced the clutch a little over a year ago and I suppose I got lucky with torquing the trans down; I had to chase that ears threads out but didn't have any other issues so didn't think much of it. This time around it started to tighten up and just went loose with a pop sound.

Short of dropping another engine into the Jeep, what would be the best way to fix this issue? I know that brazing or nickel rod are good methods for cast iron, but my experience with those methods are limited, and don't know what would be best. I can't imagine this being repairable without removing the engine, so would there be any problems running without that bolt until it can be repaired?

I've found a few other similar situations on other forums, and it sounds like the methods mentioned above are the go-to, but I am curious as to what people here think. Pic attached is of the cracked ear, taken from below looking up towards the exhaust manifold.

 

[pagrey]

Ignore it. Make sure the other bolts are clean and installed with thread locker. If you ever have problems then replace the block. You might check the other bolts from time to time to make sure they don't shear off. Motor mount bolts often shear off the block, people find it after several are gone and the others are loose. If you keep the others in good condition it should be fine.

 

[ElectricWizard]

Ignore it. Make sure the other bolts are clean and installed with thread locker. If you ever have problems then replace the block. You might check the other bolts from time to time to make sure they don't shear off. Motor mount bolts often shear off the block, people find it after several are gone and the others are loose. If you keep the others in good condition it should be fine.

The bolts on the dowel pins are good and the other top bolt seems fine as well. This is likely what I'm going to do until I can fix it.

 

[MoneyPit89]

I did the same exact thing, on the same side, but cracked the transmission side. Any suggestions on how to fix. I've read a few places that said jb weld, something about tig welding it, and something about using a torch. Its cracked the bolt hole and went up the side some.

 

[P man]

It would bug the crap out of me but it's not going to hurt a thing..just make sure the rest of the bolts are tight and run it

 

[chimmike]

I did the same exact thing, on the same side, but cracked the transmission side. Any suggestions on how to fix. I've read a few places that said jb weld, something about tig welding it, and something about using a torch. Its cracked the bolt hole and went up the side some.

none of those will work.

 

[freedom_in_4low]

I did the same exact thing, on the same side, but cracked the transmission side. Any suggestions on how to fix. I've read a few places that said jb weld, something about tig welding it, and something about using a torch. Its cracked the bolt hole and went up the side some.

I would probably go with the same advice as above...just bolt up all the others and roll with it. I broke an ear off a transfer case once and a local fab shop said he could build it back up, and drill and tap a new hole, but the price was going to be as much as replacement. I ended up just finding another case on craigslist and swapping all mines guts into it.

Bummer luck, too. If it was a 5 speed manual you could have just swapped the bellhousing.

 

[P man]

none of those will work.

I agree skip all the above and just run the damn thing

I parted out a jeep recently and there was 1 cross threaded bolt and 1 other bolt mating the transmission to the engine and the dude drove it daily before he wrecked it...I personally would round up a good block and wait for a rainy month to swap it out but in the meantime "send it"

 

[ElectricWizard]

I would probably go with the same advice as above...just bolt up all the others and roll with it. I broke an ear off a transfer case once and a local fab shop said he could build it back up, and drill and tap a new hole, but the price was going to be as much as replacement. I ended up just finding another case on craigslist and swapping all mines guts into it.

Bummer luck, too. If it was a 5 speed manual you could have just swapped the bellhousing.

I've ran it this way since this posting without any issues. As long as your two dowel bolts and the other E12 are good you should be okay.

The bell housing on the AX15 and NV trans are also replaceable; I'm not sure if the auto bellhouaings are.

 

[ElectricWizard]

It would bug the crap out of me but it's not going to hurt a thing..just make sure the rest of the bolts are tight and run it

No problems so far, but man every time I remember it I'm sure bummed/pissed.

 

[MoneyPit89]

My bad, It is the dowel bolt on the driverside. Sorry I dont know the correct terminology names for a lot parts. This is the first time, I've ever worked on a transmission, period. I dropped it by myself, had a shop rebuild it, and trying to put it in myself has become a pain.

 

[ElectricWizard]

My bad, It is the dowel bolt on the driverside. Sorry I dont know the correct terminology names for a lot parts. This is the first time, I've ever worked on a transmission, period. I dropped it by myself, had a shop rebuild it, and trying to put it in myself has become a pain.

Eh, might still be fine, but I'd be uncomfortable about it personally.

The dowel pins are important and I'd imagine a missing bolt in that spot would cause problems.

One of the few threads I found on this topic was of a guy in a similar situation to yours, with a stripped and missing dowel pin bolt. He ran it and eventually had his trans blow. Your mileage may vary.

 

[macleanflood]

You could make a bracket that hits other engine bolts...like off that manifold bolt above...and bolt the transmission to said bracket. Try and hit at least 2 and preferably 3 and 4 bolt holes.

That's what I would do.

-Mac

 

[Paul Land]

I had my transmission out in order to fix some leaks, and upon reinstalling it while torquing up the top-driver side bellhousing bolt, one of the E12 ones, the ear on the engine it threads to cracked clean off the block.

Oops!!! Have Reputable weld shop for around $100.00 build-up Aluminum Flange and Drill and Tap. Use torque wrench and torque all bolts to specs this time.

 

[ElectricWizard]

Oops!!! Have Reputable weld shop for around $100.00 build-up Aluminum Flange and Drill and Tap. Use torque wrench and torque all bolts to specs this time.

During my research I came to the conclusion that most shops are reluctant to take on a job like this due to the block being cast iron. The ones that are will charge big $$$.
I plan on brazing it up with silicon bronze whenever I feel like pulling the engine. Running it as is so far has been fine so I'm not in a rush!

Also, the real cause of this problem and main take-away is that the PO of my jeep replaced the E12 bolts with ones that were too long.

 

[williambmac]

none of those will work.

Why not? Tig welding the tab back onto an aluminum bellhousing is perfectly fine if done correctly. We've done it numerous times without and issue.

The bell housing on the AX15 and NV trans are also replaceable.

They are also interchangable

 

[chimmike]

Why not? Tig welding the tab back onto an aluminum bellhousing is perfectly fine if done correctly. We've done it numerous times without and issue.

Welding cast aluminum is a crapshoot. If you hit an air pocket, you're screwed.

 

[sq8810]

You could make a bracket that hits other engine bolts...like off that manifold bolt above...and bolt the transmission to said bracket. Try and hit at least 2 and preferably 3 and 4 bolt holes.

That's what I would do.

-Mac

Do you know of anyone who has done this before? The ear on my block which holds the driver side dowel pin on a fresher 4.0L I was putting in cracked last night...

 

[macleanflood]

Do you know of anyone who has done this before? The ear on my block which holds the driver side dowel pin on a fresher 4.0L I was putting in cracked last night...

Specifically in just that scenario no... generically speaking I've done similar things to many vehicles over the years.

That being said the dowell pin is pretty fing critical and I'd probably take it to a machine shop...or try it myself...and carbide bit out the crack and TIG or braze it back together.

Dowell pin locates everything...so that's not necessarily something you want to wing ding on round 1...try 7 maybe...

You're talking cast steel now and not the aluminum bell housing. If it's a fresh build then it might be cleanish. Might.

-Mac

 

[mrblaine]

You're talking cast steel now
-Mac

Not that it matters for anyone in a shop that would try the repair but the block is cast iron and depending on the alloy, can be pretty weldable or next to impossible. If it was indeed cast steel, it would weld like any other steel with ease. It isn't.