More Turbo 400 questions

sl1111

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Forgive my lack of education about these trannys, but I have always had transaxle cars in the past. I took my trans out of my new to me truggy and noticed 2 cracks on either side of the vacuum modulator. They both have a little bit of transmission fluid weeping from them.

Can they be repaired?
Is this common?

I noted a small Tig weld on the bellhousing from another incident and assume welding is an option. Just trying to sort it out......




Thanks
 

85yota

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I would just get a new case and have the internals swapped over and maybe freshen it up while its apart. I can get cases for less than $100 all day long at junkyards and most of the time I can get them for around $50.00 so that's what I personally would do.
 

philofab

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The area where yours is cracked is difficult to repair correctly. A new case is your best bet.
 

manicmechanic

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Im thinking case swap also. I have seen a few broken bell housings, mostly in stock chevy 4 by 4 trucks that caught some air. Always wondered about the loads the wieght of the engine and the t/case causing the transmission case to fail when it all lands hard enough to break your butt! That mount on the tail housing is a long way from the engine mount!!!. Always wondered if better engine support and t/case support would help. Better suspension and saner operator would probably go along way to.
P/S never had any cracks around the modulator.
Short course, the vaccum modulator increases the pressure in the trans when vaccum is low in the engine "high power output" Decreases the pressure in the trans when vaccum is high "idle". Most modulators have a screw inside the hole the vaccum hose plugs into. for a later shift, screw clockwise. Some shift kits eliminate the modulater for manual shift.
 

sl1111

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I am such a Dip **BAN ME****BAN ME****BAN ME****BAN ME****BAN ME**..... Took the transmission in today and told the builder that my transmission is cracked at the modulator. He says in 25 years he has never seen a case crack there. I take him out and pointed out the crack and weeping to the builder. He looked at me and smiled....... Grabs a rag and some parts cleaner and cleans the area. Tada....... no crack, just really rough or in his words "crude" casting marks. The weep is from where the modulator had a little blow by at the hose.

Needles to say he is still doing a refresh and putting a manual valve body in it for me.
 

manicmechanic

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Those castings can be rather rough. I have seen some that even seemed have been welded/repaired at the plant. Older ones with rough casting may even be tougher!
Way back in a chrysler school, I remember hearing that the first 727 case was the largest single piece aluminum casting ever made at the time. The last 727 casting was probably a little rough to. Same mold?
 
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