Welding aluminum transmission housing

A buddy of mine had a mount ear put back on his M3 trans teh other day, TIG would definately be the method of choice for aluminum, MIG could be gotten by with in a pinch though.
 
Don't bother if you mig weld it. Due to the porous nature of cast and the lack of cleaning that a mig arc doesn't allow you'd end up with a very porous and weak weld. The part must be very clean and a fully penetrated bevel would be very helpful. At least a 200 amp machine would make life easier and some generous preheat. However, if your going to attemp it assembled; depending on the location, mig may be the only way to keep it cool enough not to damage seals, but imo it would be a band-aid repair.
 
In the hands of a good welder, it is a very viable and affordable repair option. The problem is, it's VERY labor intensive. Prep work on something like this takes forever because, like stated before, aluminum soaks up contaminants like oil and grime. I'd weld it, though.
 
an option not mentioned would be to stick weld the aluminum. It would be much better than the MIG and is a little more resistant to contaminants on the metal
 
The transmission also has an internal issue which sucks since it only has 15k on it. I'm going to open it up and see what the problem is. If it's going to cost a butt load of money to repair I might be looking for a used one. If not I'll be looking for a welder to repair the mounting ear.
 
rockcity said:
an option not mentioned would be to stick weld the aluminum. It would be much better than the MIG and is a little more resistant to contaminants on the metal
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I have used stick Aluminum extensively, it takes A lot of skill to make A half decent weld, on light gage metal. I'd consider it to be Very difficult, for heavy stuff, especially high stress applications like this.
 
buckshot500 said:
I have used stick Aluminum extensively, it takes A lot of skill to make A half decent weld, on light gage metal. I'd consider it to be Very difficult, for heavy stuff, especially high stress applications like this.
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difficult, yes. But, its much better than MIG welding it plus it welds much better than TIG if the metal is containimated with oil, dirt, etc. etc. that can't be cleaned easily.

Take your time with the stick as well. I've used it on hundreds of cast aluminum repairs with great success, even on outboard motor housings without dissassemble.

I'd TIG if possible or stick weld it if TIG isn't available, but stay away from MIG.
 
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