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th400 problems :(

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Old 10-20-2006, 11:18 AM
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Default th400 problems :(

i just finished from installing a th400 in a friends camaro and it seems it has issues .

first off the tranny is a fresh rebuild with borgwarner clutches and a transgo shift kit.

what is happening is that the car does not shift when you tell it to , i.e. you floor it and at lets say 5k rpm you hit the shifter and the car keeps pulling to the 7200 revlimiter. and when is shifts its not as hard as you'd think the shift kit would make it be ( that is taking into concideration that it has a huge stall)

the car has 4.56 gears, 5500 stall and a BIG cam. i checked the vaccum line and its ok.
what could be causing this? could it be something related to the lack of vaccume because of the big cam??
Old 10-20-2006, 11:24 AM
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low vacum will cause late shifts on the hydramatic 400 though it should cause the shifts to be more agressive . How does it shift at light throttle ?
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Old 10-20-2006, 12:46 PM
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Make shure you have the 12 volt kick down switch wired up to the transmission so it will know that you are are at WOT
Old 10-21-2006, 10:39 AM
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didn't know you needed the kickdown switch to be wired up for the tranny to give you full line pressure if you had a shft kit installed?

any how, i pulled the governer and one of the springs was missing. would that cause the problem?

i pulled another governer from another th400 i had and put it in there, only thing is the "new" governer has heavier weights. what would that do?
Old 10-21-2006, 10:42 AM
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and i'll have to get back to you onthe part throttle shift, don't think i tried that, or maybe i havn't noticed it.
wouldn't low vacume tell the tranny that the car is accelerating, thus it should give full pressure?
Old 10-21-2006, 11:23 AM
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Yes Low Vacume Should Give High Line And Late Or Delayed Shifts With The 400,as For The Heaver Weights On The Replacement Govenor It May Cause The Shifts To Occur Earlier ,but Shouldnt Hurt Anything ,
As For The Kickdown Solinod It Does Several Things But Basically Serves The Same Purpose As The Kickdown Cable On A 350 , It Raises All Shift Points And Facilitates Downshift To Second Or First When The Car Is Floored In Drive Depending On Govenor Presure On Which Is Allowed ,
Sorry For Caps Button Is Stuck Lol
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Old 10-22-2006, 11:33 AM
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well , i installed a vacume canister and it still does the same. shifts seem a bit mushy to me but like i said it has an 8 inch converter.

the thing i'm not getting is the whole vaccume thing. on my supercharged camaro i have the hose connected directly from the manifold to the modulator , and tha car shifts perfectly at 6200 when in d or when ever i shift it at ( with a very slight delay). why is the other tranny doing the opposite?
Old 10-22-2006, 01:02 PM
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Its increasingly sounding like you have some internal transmission problem
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Old 10-22-2006, 06:57 PM
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ha mine doesnt always shift into third,been like that since i got it ,i have to shift back to second then back to third again to get it to shift,mine has a transbrake though,and i know it isnt my cable adjustment like i thought,good luck im about to put my other trans in thats for my 70 chevelle.i give up!
Old 11-02-2006, 05:55 PM
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well we still have the same problem , even after installing a vaccume reservois and check valves.

we already ordered a manual valve body, hope that cures it.
Old 11-02-2006, 06:21 PM
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That would have no choice but to cure it unless its slipping or something
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