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How to repair cast aluminum transmission case

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lbcfan

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My ribcase jumped off the bench today and a 3" piece cracked off- right at the top where it joins to the engine.
The broken piece contains a bolt hole- it cracked at the tab hole.

Given that the case has been soaked in oil for a few decades is it practical to have it welded or brazed successfully? Has anyone tried?

Would using an epoxy or other adhesive be practical? I have a perfect (rough) joint between the piece and the case.

Thanks.

Michael
 
Sorry to hear that Michael.

Either have it welded or clean it really well and try JB Weld. Use the original 24 hour formula, not the JB-Kwik. Figure out a way you can keep the piece from moving for the 1st 4-6 hrs, then apply epoxy to both surfaces. You should allow it to overlap the crack on both sides. I stabilize/prevent it from running by putting masking tape over it, smoothing the epoxy out underneath. The stuff is very strong and should work well if your surfaces are prepped right.
 
I vote for welding. In the old days the method was called Heliarc. Today, just call around looking for someone who can TIG weld aluminum.

I agree the 24 hour JB Weld is much better than their quick set product but I still don't think it is up to the task of repairing a break that is potentially under load.
 
A good machine shop will know to heat the pieces before welding and jig it up to do a proper knitting job. Crack needs to be bevel ground and weld beaded from inside and outside.

Perhaps supplying the engine backing plate to the shop would help in setting up the job. *hint-hint*
 
Thanks to all of you who responded. I actually called an adhesive company this morning in the vain hope that I could buy a two-part miracle. No luck...

I found a local place that claims to fix transmissions "all the time".

Dr- I have read that the parts should be heated, but I had hoped to leave the tranny intact. Can they work with that?

Michael
 
I'd not recommend that. And I'd be lookin' with a 'jaundiced eye' to a shop saying they'd do it that way.
 
There is a guy on the BCF called AweMan. I believe he is possibly the most knowledgeable person on this subject here. See if you can contact him.

I had done some welding and taught it for a Technical College but he is much better than I ever hoped to be.

Sorry, meant to say on the subject of welding.
 
I have pulled a number aluminum trans. and transfer cases that have been creatively fixed w/plastic metal products that apparently lasted quite a while before failure. Some of these fixes never failed. Strange but true. Most of them total hack jobs but one in particular a work of art, could have passed for stock but for the color change. Generally if a bolt hole is involved strength is a concern. I'd aim at a good weld. A competent welder/fabricator can fix plenty o problems for cheaper than you may think. Check it out. Ask around.
 
Shoot a photo of the trans and post it.
These are very strong cases and the upper part of the bellhousing is in compression, not tension so it is entirely possible that you could use the case as it is for a very long time even without reattaching the broken piece.
The epoxy/ JB weld could easily be sufficient and would stop dirt from entering the clutch area.
BillM
 
I'm in somewhat agreement with Bill, the case is strong and bolted in other places but I would vote for a TIG weld with the parts bolted to the engine plate and if the welder does a little at a time I would think it could be welded with the trans intact. I've done some Tig work and certified work in my youth. The job does not have to be perfect or overdone because of area IMHO. Make sure the welder knows his stuff!

Kurt.
 
are we talking about the bellhousing? If so, it might be cheaper to replace than repair.
 
If it is only one bolt hole, and the rest is undamaged, there isn't that much of a stress problem in my opinion. I think the JB fix should work fine. It will help stabilize, plus keep dirt and grime out.
 
JP--Bellhousing is not separate from the trans on a ribcage (like it is on the 1500 cars).

I'd probably try the epoxy. And maybe add a formed splice plate to join the pieces. Made from a piece of soft aluminum sheet formed over the crack. Maybe use two or four small stainless steel bolts and nuts to attach it to the joined pieces. The splice plate could be epoxied to the bellhousing as well as using the bolts.

As was said earlier, it would be nice to see a picture of it in order to give a better guess at a solution.
 
Agree, that one bolt will not be missed. Epoxy should be good. Or even just use one bolt and forget about epoxying it.
 
What I would do. bend a piece of steel and put a scab plate on the inside and bolt it though on the undamaged part and again on the piece and get it all squared that way and it should work. Welding cast aluminum is questionable. I am sure some can do it, but I would doubt the strength. There should be room in the bell housing area to shape a piece of 3/16 or 1/4 inch plate to do the job and not rub anything. Done with a scab it would probably be as strong or stronger than it was originally.
 
The USAF has been having alum welded for decades, cast of all thicknesses.

Even engine blocks and heads. No prob.
 
Back in the last Century, I had a small crack between the top two bolt holes on a ribcase. And since the neighbor was a 'Heli-Arc' welder by trade.........I asked (axed) him if he could fix it. The answer was sure..........but when he returned the case...I can remember his statement even today........'Never again with that ##$%$@% English Aluminum". :wall:

Last year I took a TIG welding class at the local higher education facility and I now can understand the problems he had. :thumbsup:

Tough duty !
 
"Dirty" aluminum.
 
Hey we're talking the highest quality JAPANESE aluminum aren't we??
Agree that aluminum with casting inclusions in it can be a pain and the piece has to be polished clean. Aluminum metal melts at a much lower temp than aluminum oxide. Also aluminum is great at transfering heat so has a tendancy to melt out a big hole in a hurry if you are not careful.
For home fix I like the idea of a formed aluminum splice plate and plenty of JB weld on a chamfered out repair. I have a tractor with the corroded out block filled in with JB weld and milled with a file! 20 years and no leaks.
 
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