welding the transmission case

[bigjblazer]

I have a TH350 with a crack in the case, its fairly small and about 5 inches long, can I weld the crack and keep all the fluid in? The trans was rebuilt just 5000 miles ago, so I'd like to try and save it. Thanks


-Justin

 

[55Willy]

do you have a pic? also bet the crack is longer then 5 inches. i would just grind a V and weld it up though.

 

[tRustyK5]

I'd lay 10-1 odds that if you weld it the weld will A) suck and B) cause even more cracking. Cast aluminum is a complete slut to weld, and it is somewhat porous so the weld will be contaminated with ATF as well.

Even if you could get it clean enough, and you managed not to melt down a nearby seal the case will likely crack even worse due to the rapid expansion caused by welding. The shape of the tranny case does not lend itself well to expansion and contraction caused by the welding.

If it were me I'd find another case and swap all the guts over.

Rene

 

[hawkeye649]

[ QUOTE ]
I'd lay 10-1 odds that if you weld it the weld will A) suck and B) cause even more cracking. Cast aluminum is a complete slut to weld, and it is somewhat porous so the weld will be contaminated with ATF as well.

Even if you could get it clean enough, and you managed not to melt down a nearby seal the case will likely crack even worse due to the rapid expansion caused by welding. The shape of the tranny case does not lend itself well to expansion and contraction caused by the welding.

If it were me I'd find another case and swap all the guts over.

Rene

[/ QUOTE ]

Yuppers, just like Rene said, cast aluminum is tough to weld. You need to have it under the proper heat conditions, just like cast iron. That means heating it up, keeping it up( /forums/images/graemlins/blush.gif ), and slowly cooling it.
Either a new case, or JB weld if that isn't a posibility.

 

[four_by_ken]

I agree with the below, so I wont type it again. /forums/images/graemlins/grin.gif

[ QUOTE ]
I'd lay 10-1 odds that if you weld it the weld will A) suck and B) cause even more cracking. Cast aluminum is a complete slut to weld, and it is somewhat porous so the weld will be contaminated with ATF as well.

Even if you could get it clean enough, and you managed not to melt down a nearby seal the case will likely crack even worse due to the rapid expansion caused by welding. The shape of the tranny case does not lend itself well to expansion and contraction caused by the welding.

If it were me I'd find another case and swap all the guts over.

Rene

[/ QUOTE ]

 

[bigjblazer]

Thanks guys, thats just what I was lookin for. So now, anyone got a th-350 layin around?