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Old 01-27-2004, 05:33 PM   #1
skokie
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Kickdown problem

I have a 350 with a 400 turbo. When I floor it it kicks down to passing gear but it wont come out of passing gear unless I drop gerars from D to L2 and back then it works. Any ideas what could be causing this?

Thanks

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Old 01-27-2004, 09:00 PM   #2
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A sticking vacume modulator, or a vacume leak feeding that line.
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Old 01-27-2004, 09:05 PM   #3
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Vacumn Modulator? How hard is that to change out?
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Old 01-27-2004, 09:38 PM   #4
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On pass side of trans-will have a vacumn line going to it-only 1 bolt to remove-pull out the old push in the new- install bolt and vacumn line-done.
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Old 01-27-2004, 10:56 PM   #5
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Ok sounds easy enuff. Should I expect a flood of tranny fluid?
Thanks
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Old 01-27-2004, 11:45 PM   #6
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no-mostly above fluid line.
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Old 01-28-2004, 01:11 AM   #7
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May do this tonight. I got the modulator.
Thanks again.
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Old 01-28-2004, 02:28 AM   #8
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Ok Modulator changed out did notice that the old hose had a crack in it. I have replaced that as well however problem still here. What else should I be checking?
Thanks
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Old 01-28-2004, 03:46 AM   #9
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um the switch on your gas pedal could be sticking? or is the switch on your carb?
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Old 01-28-2004, 01:42 PM   #10
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Does it change into high with regular driving?
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Old 01-28-2004, 03:37 PM   #11
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Switch is on the carb and I checked it. It does not appear to be sticking. It does change into high with regular driving but sometimes when you first start out you can put it in drive and it wont change to 2nd unless you change it manually from D to L2 and back again. After that as long as you dont put it in park it works fine.
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Old 01-28-2004, 04:05 PM   #12
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I wonder if it could be a problem with the fluid flow in tranny that is causing the problem. When was the last time the fluid and filter were changed?
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Old 01-28-2004, 04:25 PM   #13
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Fluid was changed out two weeks ago along with a new filter.
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Old 01-28-2004, 04:56 PM   #14
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Don't mean to hijack but I wonder if that vacuum modulator would keep the tranny from downshifting into first? Mine never drops down by it's self when I come to a stop. Anyone know?
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Old 01-28-2004, 05:34 PM   #15
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i have been having aproblem similar to 2wdblazers on my '85...it seems like it doesnt want to downshift when i slow down...vaccuum modulator?
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Old 01-28-2004, 06:05 PM   #16
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Next thing to check is the governor-it could be worn or sticking-it is the round bowl like thing on pass side of trans. The cover can be removed by taking the spring clip off. Some fluid will run out-not much. Pull ass. out and check to see it it is sticking or replace with known good one.
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Old 01-28-2004, 06:11 PM   #17
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Is it on the front of the tranny or the back on the passenger side? Where is it in relation to the vac modulator?

Thanks
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Old 01-28-2004, 06:41 PM   #18
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picture

here it is
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Old 01-28-2004, 06:47 PM   #19
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In the middle. Got it. Rookier question here but what should I do to test it?

Thanks
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Old 01-28-2004, 06:47 PM   #20
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picture

Sorry wrong picture--here is the 400
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Old 01-28-2004, 06:53 PM   #21
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The weights should move in and out easy-as the weights spin then move outward causing the shaft to cover or uncover holes to make trans shift. I am not a trans expert either so I do not refund any money on advice. LOL
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Old 01-28-2004, 08:03 PM   #22
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that still sounds like straight up vaccum problems to me. I'm no tranny expert by any means either though. You've changed the modulator and changed the rubber line but have you changed the whole line to a rubber piece? The line itself should be metal most of the way except for where it plugs in at the tranny and at the manifold. I'd check to make sure you got a good connection at the right spot on the manifold too. I see some people that run all rubber hoses for the vaccum advance on the tranny and the hoses will loose there strength cause of the heat and they will collapse and not get proper vaccum through. thats my 2 cents
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Old 01-28-2004, 08:23 PM   #23
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Its 2-3 inches of rubber line to the manifold, 2-3 inches or rubber to the modulator. The rest is all metal. I am going to remove the metal line tonight and see if anything is stuck in there and give it a good cleaning.
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Old 01-29-2004, 01:46 AM   #24
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Ok here is a pic of the setup behind the carb. Its a 3/8 nipple in the manifold with a 3-4 inch piece of 3/8 tube going into a 3/8 and 1/4 tee. The 1/4 tee is connected to the metal tranny line going to the modulator. Is it ok to tee this off? Not sure why it was done this way.

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Old 01-29-2004, 02:04 AM   #25
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hm is that connected to the back of the carb, Id much prefere to connect it to the nipple on the back of the intake manifold in the same place where the brake boost is connected
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