broken bolt on modulator valve

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potent rodent

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hey all , the tang with the bolt hole on my 86 gmc turbo 350 broke off , i was going down the road and it blew the mod valve out and lost all my fluid , any ideas on how to keep the mod valve in the tranny
 

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hey all , the tang with the bolt hole on my 86 gmc turbo 350 broke off , i was going down the road and it blew the mod valve out and lost all my fluid , any ideas on how to keep the mod valve in the tranny
Get the correct thread helicoil or time sert. You will need to drill the hole to the right size and then tap it to the insert thread. Make sure you buy a kit with the proper size drill bit and tap for the insert you are buying. The resulting threaded hole will be stronger than the original.

I dont remember what size the hold down bolt is, but if it was a 1/2" headed bolt, you will need this one:
https://www.amazon.com/dp/B0002SRDUU/

A 7/16" headed bolt would need a 1/4-20 insert kit.

You can also get them locally at most parts and hardware stores.
 

potent rodent

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there is nothing there to tap , were the bolt screws into its broke of flush with the tranny
 

AuroraGirl

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there is nothing there to tap , were the bolt screws into its broke of flush with the tranny
So you need to drill out or you need to remove a broken screw/fastener.

Tell me that you have done that before? It sucks sometimes but you at least arent trying to do it through a opening on a harmonic balancer and you cant physically be close you have to do it at arms extension. You can be right in there. drill out since you have to go larger anyway, you can also get left handed drill bits and other extractors


so none of this "nothing to tap"
there is metal there

it can be tapped

Just depends on your willingness to get in the ring, tiger

We were talking about fasteners, right..?
 

potent rodent

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i was a heavy duty diesel mech for 30years and also gas , i think i can drill and tap a hole . like i said the tab were the bolt screws in to it broke off flush with the trans case i dont think u can drill in to that and tap
 

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Dont shoot me!, i think some pics are needed here... there appears to be confusion amongst us....
 

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i dont have a cell phone to take pics with, i will try and send some pics thanks all for the help
 

potent rodent

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Your 2 choices here are, a new/used replacement trans case, or tig weld a new mount to the case.
i was leaning to tig welding it back on also , nooooooooooo trans swap, truck is just for hauling wood and and an all around work truck , thought maybe some one had been through this same thing
 

Bextreme04

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Your 2 choices here are, a new/used replacement trans case, or tig weld a new mount to the case.
I agree, I was under the impression that the bolt had stripped the hole out. It's been a while since I've seen a TH350 in person. Do you have the original piece that broke off? What the heck caused it to break off? Its on the back of the trans, so the only thing I could think of is that something on the road got kicked up and hit it? I can't imagine the trans would have enough pressure there to actually push it out.
 

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There are repair brackets available in the aftermarket to fix this exact problem.


If you have the trans out of the truck, and can weld aluminum, obviously that’s the way to go. The repair brackets are a decent alternative.
 
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AuroraGirl

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Your 2 choices here are, a new/used replacement trans case, or tig weld a new mount to the case.
No no no, turbo, Its really late hour of the night, Im tired as hell and was thinking about sugar cookies before I clicked on this notification, but I have a plan
it involves a scribing tool or dremel or something to that effect(scribing tool if you are bored and want to burn time?)

OP needs to clean up the area with degreaser, make a hatched area to increase surface area that can be grabbed onto by STEELSTICK or whatever JB weld for metal thing / any other maker for metals and also the broken piece too, and have at it. let that cure, follow the instructions.
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probably unstick the thing that broke it off too before all that maybe but I dont judge



now, unrelated, but for the ***** and giggles should I try to fix this with this:
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Just needs minor cleaning out and its a good tank again :(
 

AuroraGirl

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There are repair brackets available in the aftermarket to fix this exact problem.


If you have the trans out of the truck, and can weld aluminum, obviously that’s the way to go. The repair brackets are a decent alternative.
****. didnt see your comment before my elaborate idea to rig it.

I guess for that special someone out there who specializes in doing something that would end up being more work, for probably not cheaper, with a larger time investment, and maybe with success maybe not... and that will still be the obvious fix for them. god bless their deviant nature.
 

potent rodent

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I agree, I was under the impression that the bolt had stripped the hole out. It's been a while since I've seen a TH350 in person. Do you have the original piece that broke off? What the heck caused it to break off? Its on the back of the trans, so the only thing I could think of is that something on the road got kicked up and hit it? I can't imagine the trans would have enough pressure there to actually push it out.
no its out there on the road dont know what caused it didnt see anything in the road .
 

potent rodent

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****. didnt see your comment before my elaborate idea to rig it.

I guess for that special someone out there who specializes in doing something that would end up being more work, for probably not cheaper, with a larger time investment, and maybe with success maybe not... and that will still be the obvious fix for them. god bless their deviant nature.
thank u for the web site that just might work have a great day and thanks for the help
 

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