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Old 10-31-2015, 10:15 PM   #1
9teen69
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XMSN swap complete but not shifting auto...

I finished...kinda my transmission swap today. 3OTT to a TH350 and it doesn't shift automatically Did I hook something up wrong or maybe it's a manual valve body? I have the vacuum line running from the modulator on xmsn to the vacuum advance on the HEI ready dizzy.

It shifts fine when I start out in 1, 2 then 3. So I'm super happy for the most part

I don't know the history nor does the board member I bought it from.

Also wanted to say thanks to everyone on the site for their help current and past post.
Column linkage like this saved me so much time
http://67-72chevytrucks.com/vboard/s...d.php?t=491049

Rebuilding my column, even when I didn't read " Metal one goes in first." on post 8 and took me a day to figure it out.
http://67-72chevytrucks.com/vboard/s...d.php?t=630848

Thanks for the help.
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72 Cheyenne SWB C10 (daily driver)
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70 Camaro RS (frame-off in pieces)
70 Camaro RS (daily driver backup)
69 Custom LWB C10 (son now drives)

Last edited by 9teen69; 10-31-2015 at 10:22 PM.
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Old 10-31-2015, 10:16 PM   #2
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Re: XMSN swap complete but not shifting auto...

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Last edited by 9teen69; 10-31-2015 at 10:25 PM.
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Old 10-31-2015, 10:44 PM   #3
firedemon
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Re: XMSN swap complete but not shifting auto...

I always thought the modulator was supposed to go to direct manifold vacume not distributor but I could be wrong
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Old 10-31-2015, 10:44 PM   #4
hugger6933
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Re: XMSN swap complete but not shifting auto...

Let me get this right, you hooked up the vac line from the trans to the Dist? That is kinda what it looks like. If so you are hooked up in the wrong place. You need Manifold vacuum weather it comes from a port under the throttle blades on the carb or the port in the back of the manifold between the card and the dist like the stock ones were. It isn't gonna shift cause the way it appears to be hooked up there is no vacuum to it. Now it also runs a little different cause there is no vacuum to the dist either. Jim
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Old 10-31-2015, 10:52 PM   #5
9teen69
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Re: XMSN swap complete but not shifting auto...

Ahhh grasshopper. So I should hook the disto back up to the red plugged port and hook the trans mod to the black plugged port.

I'm a dork but that's going to be an easy fix. Thank You!
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72 Cheyenne SWB C10 (daily driver)
(Super fake cause I just love the glovebox emblem)
70 Camaro RS (frame-off in pieces)
70 Camaro RS (daily driver backup)
69 Custom LWB C10 (son now drives)
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Old 11-01-2015, 10:42 AM   #6
hugger6933
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Re: XMSN swap complete but not shifting auto...

Your trans should be hooked to MANIFOLD vac. That would be the one under the throttle blades in your case it is the red port under the carb. When they were"born" they had a plug in the manifold between the carb and the dist that had an angle port sticking out of it that is what they were hooked to from GM. Now it has been like 15 years or maybe longer since I have wrenched on anything with a carb on it and my old race stuff didnt have vac advance on the dist but I think your dist should be hooked to the black capped port and I know the trans should be hooked to the one where the red cap is. Try that and see if your not better off. Jim
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Old 11-02-2015, 01:46 AM   #7
9teen69
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Re: XMSN swap complete but not shifting auto...

Got the vacuum hoses hook up correctly and it's working great. Now I just have to remember to put it park, so use to leaving it first and killing it

Thanks for the help!
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Old 11-02-2015, 07:14 AM   #8
hamjet
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Re: XMSN swap complete but not shifting auto...

Quote:
Originally Posted by 9teen69 View Post
Got the vacuum hoses hook up correctly and it's working great. Now I just have to remember to put it park, so use to leaving it first and killing it

Thanks for the help!
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glad to hear it was a simple fix. I hear ya on putting it in park, when mine was a standard I always used the E- brake. now with the automatic I never use it. I guess in about 3 years it will be froze up from lack of use..
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Old 11-02-2015, 07:41 AM   #9
hugger6933
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Re: XMSN swap complete but not shifting auto...

I just noticed the pic of the trans, you don't have cooler lines? Those appear to be plugged off I hope that pic was taken before they came in or something like that cause that is like signing the death warrant. The trans needs those lines open and hooked to a cooler for that trans to last. If nothing else get an aftermarket cooler and place it somewhere were it can get some airflow. I'm not trying to dog you out or anything just trying to save you heart ache and wallet upset. The install looks real clean and I'm glad that you got the other lined out quickly. Jim
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Old 11-02-2015, 07:44 AM   #10
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Re: XMSN swap complete but not shifting auto...

Sorry, looked again the first pic shows the lines.
Again sorry very clean looking install.
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