My transfer case (aluminum) is cracked clean through right below the rear main seal and right above my idler gear bearing. Is it possible to fix this with a TIG weld? Should I instead look into brazing? The Mini WAS done… But then it started leaking at the end of the run in from what I thought was the seal going bad, but then spotted this once the clutch was removed.
BTW, if this isn’t repairable, my other option is to get a new transfer case and re setup the endfloat for the idler gear and also means getting a new set of bearings for the gears. Not the end of the world, but should be roughly the extent of the work needed for a total replacement
Obviously don’t trust advice from some rando on the internet, but:
- It’s cast, you don’t want to TIG weld it, it’s too dirty and it will contaminate the tungsten and end up with a terrible weld.
- Sometimes, you get lucky and there’s an exotic stick welding rod that claims to be able to weld whatever base material you’ve got in cast. I haven’t checked, but you might find an AC stick rod that can weld AL cast.
- TIG Brazing will work, it may or may not have the strength you need when you’re done, but it’s messed up, and you can’t really make it worse, just damage the parts when it fails catastrophically.
In any case, no matter what type of welding/brazing you’re going to want to grind out the entire affected area, bevel the edges, and drill the terminating points of the crack “to stop the crack” look into techniques on this, everyone has their own way, but I like to put the center of the drill hole where “there’s no possible way the crack could have made it to here” and then weld/braze too much vs too little.
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sounds a bit like a replacement will be the more economical option and takes the guesswork out of how long a repair may last
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What kind of money are you talking? I’m thinking you’re looking at 8 or 9 hours of prep, pre-heat, weld, and post-heat, then replacing the bearings anyway and potentially needing to mill/lathe things back into true if your heating and cooling caused warp. It’s doable, but it’s a weekends work, and I’d take the couple hundred dollar replacement option in a heartbeat if it was mine.
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New case and bearings, not including shipping, will run a touch over $200. Replacement is in order then sounds like.
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Which, if anyone in Automotive was wondering what happened to that Orange Mini… It’s almost a year later since I did the teardown, I “finished” the rebuild in March, but it has been one thing after another. I JUST did run in and was going to get it inspected a couple of months ago when I discovered the oil leak. Thought it was the rear main seal in the clutch housing, but it’s this giant crack that I’ve been scratching my head over. Maybe I’ll get it finished by the end of the year… who knows 
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Looking at what looks like a network of cracks around near a lot of bearings, I’d be afraid of alignment issues when it is done - even if the strength is there. If it is $200, I’d get the new case and not worry about losing all the hours @malcolmputer is talking about and especially not worrying about it failing catastrophically and costing you more in parts and towing and possibly injury if it fails at a bad moment - which it will.
With the the old case - then practice brazing it … and realize you were smart to replace it!
@Omnomsan
I agree with Malcom. The $200 is way less than repeating the tear down and rebuild if the weld doesn’t work.
If you are trashing the housing I’d love to take it off your hands.