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CRACKED TH350 CASE

Discussion in 'The Garage' started by bigjblazer, Sep 15, 2004.

  1. bigjblazer

    bigjblazer Registered Member

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    Is it possible to weld up a crack on a transmission case? the crack is about 4" long and right behind the rear of the pan, heading into the T-case. I originally thought the trans was blowing all the fluid out of the pan gasket, but when ever the truck is started, it just shoots out of this crack.

    The transmission was completely rebuilt last year, and has had roughly 3000 miles on it since then. If the truck was driven for maybe, 200 feet while the fluid was spit out, should the internals be in well enough shape to swap into a new case if necessary?

    This occured when I let my roommate drive my truck for one day. How can you crack a transmission case, while driving it on the street?

    Thanks for any help.
    -Justin
     
  2. RustBuket

    RustBuket 1/2 ton status

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    Tranny cases are usally cast iron or aluminum are they not? This means you need a professional welder trained to weld that certain kind of metal but you could probably have it done.
     
  3. diesel4me

    diesel4me 1 ton status Premium Member

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    You probably wont have any luck welding it--it is doubtful the crack is only on the outside of the case--most likely the internal"rats maize"of passageways inside the case are cracked also,allowing the pressure to go to the other passages,so its probably a lost cause--you may not have ruined all the clutches and internals,so maybe you could install your "guts"into another good case.
    Its not hard to crack a tranny--even on road--shifting from R to D while rolling at speed will do it,I've seen a K5 at the mall drop the transfer case right on the ground when a impatient female driver passed a few slower cars and went over some speed bumps about 30mph(I laughed so hard I almost peed myself!).That die-cast aluminum or magnesium that a tranny is made of isnt that strong,you can crack it with a hammer pretty easy--I still cant figure out how they live with only 4 3/8 bolts holding a 200 lb 205 transfer case,especially on the years that had no brackets to the frame,or those rods to the bellhousing bolts.
    I have 3 useable cases in my shed,the cases are good but the trannys are junk--your about the third one on here in a week or so who has a cracked case--If you were near me I'd sell em real cheap--I'm deep in debt from my recent motor swap,my insurance payment is due today,and my other truck has a flat tire and 1 of the injector lines just rusted through and started leaking~ /forums/images/graemlins/1zhelp.gif
     
  4. BadDog

    BadDog SOL Staff Member Super Moderator Author

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    It's cast aluminum and I would forget fixing it. And I'm putting "my money where my mouth is" as I've been forced to do on the new trans that came in cracked.

    As for the "rats maze", that’s in the valve body, not the case. Back there is nothing but the planetaries and rear clutch drum assembly (as well as the governor on the side). Probably ok as far as that goes. It’s also quite possible that the guts are fine and you might be able to put them in another donor case if you can find one cheap. Labor to just swap things over and hot tank the new case should not be too bad if you r/r yourself…
     

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