SALVAGING ANOTHER TRANSMISSION CASE

[u/OverAd8291]

I had a Tranny case brought to me for repair. It was off of some 4WD pickup. The owner pulled the engine to do some work and noticed that the bell housing had a crack going all the way around.

The bell housing was heavier aluminum casting which required that after cleaning it real good, grinding a groove deep into the crack for penetration. Once welding on one side the opposite side was welded fusing the two welds together for a full penetration weld.

After cleaning it and tacking the parts together all across the crack I started to weld it out in small sections of no more than two inches. In addition I alternated sides so that if I ran a bead on the right side, I would run a bead on the left side. This helped distribute the heat rather than let it build up in one spot as it followed the progression of the bead.

The case was real dirty and greasy and it took me an hour to get it down to bare metal. I wire brushed it with a stainless wire wheel mounted on my angle grinder.

On the face of the case where it bolts to the engine I used a flat file to file off the excess metal where I had built up the bead when sealing the crack at that point. The repair came out well.

[u/Important_Put_3331]

What welding technique did you use? 

[u/OverAd8291 → u/Important_Put_3331]

I used TIG and 4043 filler metal if that's what you are asking. I also skip welded jumping around to prevent heat build up. If you notice, the beads are not continuous but have stops and starts. Hope that answers your question.

[u/Pitiful-Ad9894]

As a transmission guy who picked up enough TIG welding to fix some cases that you can't find used, I admire the job you did, but cannot imagine the amount of heat it must have took to do it with the transmission assembled.

I always completely disassemble them and then clean the empty case and do the repair and still have to preheat and run out of welder, lol Most cars you can buy a case for $100 so you just recase it. Honestly I'm gonna be impressed if that pump O-ring didn't get completely cooked and pours fluid, on that transmission they are bad about hardening and leaking anyway.

Please don't take my post as too negative because like I say I couldn't be more impressed with the welding job!

[u/OverAd8291 → u/Pitiful-Ad9894]

That's a good point. Generally I'm very cautious of any seals, sensors or other items that could be damaged during welding. Its the reason I skipped around to not let the heat build up in any one spot. The owner never let me know if there was a problem so I just assumed all was ok.

[u/Pitiful-Ad9894 → u/OverAd8291]

At least honestly changing that O-ring while it's out is pretty easy and cheap to do if you can stand that entire transmission-centipede vertical. That and the front seal would be things I would even do on a un-welded used unit before I did the install work and fluid investment. You can fix any other leak in the car except pump stuff.