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Old 09-18-2014, 06:58 PM   #1
carnut4real
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broken trans modulator bolt

anyone ever have any luck removing a broken bolt on the transmission modulator clamp or come up with an alternative way to keep it in ? it's on a 1979 suburban 4x4 I just bought, and there is no way I'm getting in there with a drill.
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Old 09-18-2014, 07:58 PM   #2
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Re: broken trans modulator bolt

What about an Easy-Out and a stubby tap handle or small crescent wrench?
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Old 09-18-2014, 08:41 PM   #3
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Re: broken trans modulator bolt

Try merely rotating it out by tapping it with a punch and a hammer.

Unless the bolt was the wrong one and was sheared off after it bottomed in the hole, it should be loose enough to persuade out.
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Old 09-18-2014, 08:49 PM   #4
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Re: broken trans modulator bolt

Aluminum transmission housing and steel bolt, it might be seized in there. Sure it sucks, but you may have to pull the transmission.
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Old 09-18-2014, 09:13 PM   #5
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Re: broken trans modulator bolt

If it's a th350 worst case you have to pull the transfer case to get clearance to drill it. If it's a th400 you should be able to unbolt front drive shaft and the cross member and lower the Trans enough to clear to drill just don't break your distributor. Or if the bolt is broken flush you can put a 5/16 nut over the broken bolt and weld the center so it welds to the damaged bolt and then the heat will help break it free.
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Old 09-18-2014, 11:34 PM   #6
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Re: broken trans modulator bolt

What's with everybody who wants to pull the tranny, or tear it apart or drill out the bolt that's impossible to get at.
Get creative and build a simple bracket to replace the one there. Use existing bolts on the pan or the bell.
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Old 09-19-2014, 01:04 AM   #7
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Re: broken trans modulator bolt

Just use duct tape.
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Old 09-25-2014, 08:08 PM   #8
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Re: broken trans modulator bolt

I ended up fabricating an alternative way to fasten, but I changed the modulator valve, fluid and filter, and the transmission is still shifting at really high rpms ?
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Old 09-25-2014, 08:08 PM   #9
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Re: broken trans modulator bolt

I have good vacuum also
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Old 09-25-2014, 09:51 PM   #10
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Re: broken trans modulator bolt

So, just adjust the modulator!
A small flat head screwdriver will work.
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Old 09-25-2014, 09:55 PM   #11
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Re: broken trans modulator bolt

I'll give it a shot. I figured it would preset
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Old 09-25-2014, 10:01 PM   #12
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Re: broken trans modulator bolt

It's acting the same as it did before Changed it could it be the governor
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Old 09-25-2014, 11:38 PM   #13
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Re: broken trans modulator bolt

Late shifting or early shifting is usually modulator.
They aren't pre-set.
Be aggressive in your adjustments. Don't go just one turn at a time.
IIRC turning it out is the way to go.
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Old 09-27-2014, 01:26 PM   #14
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Re: broken trans modulator bolt

Geezer thanks for the info, let me ask you this, is the fluid suppose to run out when the modulator is removed ? I've turned it out multiple turns with no results, but thought I had read somewhere that there shouldn't be much fluid behind it ?
Thanks
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Old 09-27-2014, 01:56 PM   #15
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Re: broken trans modulator bolt

Yes! A little fluid comes out when you remove it.
Did you make sure the pin was put back in when you installed the new one?
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Old 09-27-2014, 01:58 PM   #16
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Re: broken trans modulator bolt

I can feel the pin in there, and I never did remove it, but the fluid is running out
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Old 09-27-2014, 02:16 PM   #17
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Re: broken trans modulator bolt

If you pull the hose off, no fluid should come out.
You do know the screw for adjustment is inside the hose nipple.
Can you see the screw end when you look in there?
The pin goes in the end of the modulator when you install the modulator back in the tranny.
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Old 09-27-2014, 02:46 PM   #18
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Re: broken trans modulator bolt

I do know how to adjust it, but it is in such a tight area that I have to remove it to adjust it. I can't even fit a small screw driver from an eye glass kit between the transfer, and modulator. I was not aware that the pin is small enough to fit in the modulator, as my knowledge of the transmission is limited. maybe the pin is missing, and that is why fluid is pissing out ? I changed it in my garage, and saw nothing come out, but it could have fallen on the support or something ? I have no way of looking in the hole where the modulator goes, so not sure how to prove whether the pin exist or not ?
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Old 09-27-2014, 03:21 PM   #19
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Re: broken trans modulator bolt

The pin is about 1 inch long and looks like a small nail.
To see in a tight spot use a mirror and a flashlight. Shine the light in the mirror and angle the mirror where you want to see.
Maybe you didn't have the pin in there to start with. PO might have lost it.
No pin would cause your high shifting problem.
The pin slides right in the end of the modulator.
To make a tight fit 90 degree screwdriver I've used an allen wrench ground down on the end to fit in the hole.
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Old 09-27-2014, 03:28 PM   #20
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Re: broken trans modulator bolt

Ok, I'll give it a try. I found a used pin on eBay, and it look like a small cam shaft. It's actually within driving distance of me, will the pin stick out or could it be flush with the hole it sits in, because when I put my finger in there I can feel something move, but it's flush ?
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Old 09-27-2014, 03:32 PM   #21
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Re: broken trans modulator bolt

THe pin should fall out IIRC.
And It should stick out, not flush.
When you take it out, take a pic of it.
In fact, take a pic of the modulator before you pull it out.
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Old 09-27-2014, 04:14 PM   #22
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Re: broken trans modulator bolt

ok, so I pulled the pin out with a pair of tweezers, and it looks like a cam shaft about 2.5" long. The last 1/8" appears to be spring loaded, so I'm not getting the modulator in all the way with the strap I made up. If this is causing the issue I am going to have to remove the broken bolt, so I can use the stock clamp ?
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Old 09-27-2014, 04:32 PM   #23
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Re: broken trans modulator bolt

Is there a chance of a pic?
I don't recall a pin like that.
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Old 09-27-2014, 04:50 PM   #24
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Re: broken trans modulator bolt

http://i.ebayimg.com/00/s/MTE5NVgxNjAw/z/siwAAOSwPe1UFKFF/$_57.JPG
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Old 09-27-2014, 05:16 PM   #25
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Re: broken trans modulator bolt

Linky no worky!!
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