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I am the Antirice
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270 Posts
Discussion Starter · #1 ·
I know, it sounds crazy, but they look just as crazy (to me at least). Hopefully I'm just too paranoid, but when I cleaning and inspecting my TH350 after pulling it and the motor out of the chevelle preparing for the new motor, I found these. Now, at first I thought it was flaking paint but after looking closer and brusing it off, I notice that these are like a mass amount of spiderweb style cracks, betting bigger towards the tailhousing. I've never had any problems with this transmission, in fact, it was just rebuilt a couple years ago, and there haven't really been many miles put on it, the car only gets driven every few weekends, and for one year, the car wasn't driven at all because of body work. Is this bad? Or is this some sort of casting issue with aluminum cases, and it's only on the outside, and will be for years to come. Who knows, they may of been there when I put it in the car and never noticed it.

I would put pics into the thread, but these are huge res for the detail, so I'll just give you the link.


http://project71.net/skeeveman/Tranny/

Thanks in advance, guys!
 

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I am the Antirice
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270 Posts
Discussion Starter · #3 ·
Man, I sure hope so, I hope it's just my tired eyes and mind playing tricks on me.

Like I said, it's treated me great this whole time. Also the guy that built it would of said that it was no good if he was concerned, he's never built me a bunk tranny in the past, I'm sure he would of told me if he was concerned.
 

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I happen to have 3 or 4 TH350's and a few TH400's out back, one is just a bare TH350 case...none look like that as i recall.

Im not saying you have a problem, but all the webbing and such I've ever noticed on the Al stuff, seemed to be "on top" and not "in" the case.
 

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Those "cracks" are the result of the die or mould not being heated up to temperature when the aluminum was shot into the mould. The outside gets this "crackly" finish from the molten aluminum hardening too wuickly. It is a surface flaw only. I've seen many aluminum transmission cases with this pattern. Fubctionally AOK but don't chose one like this to polish real pretty.
 

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Hates: Liver. Loves: Diesel
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6,303 Posts
Agreed. Cold molds make "boil" marks where the hot aluminum causes outgassing against the mold surface. It makes random "crack" looking parts in the casting which explains why some have it and some don't. Feel it with your finger. If its above the surface, its fine. If its below the surface, its not.

... but it would be rare for it to be cracked in the same manner that the casting boils appear, so I think you're fine.
 
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