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Transmission locks up hard

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Old 01-12-2005, 02:05 AM
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Default Transmission locks up hard

I just put a torque converter in, about 100 miles ago. About once every time I drive overdrive will lock up and it will lock up hard, like you can feel it in your pants. Is this something to be concerned about? Seems to drive perfectly fine and shifts great.
Old 01-12-2005, 02:37 AM
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Mine goes into lockup very hard too, I have the Yank ST3500... I have found though after driving it for a while that I can tell when it is going to lock up and go easy on the trottle... If you floor it from a roll (dispite the tire melting fury) it does not do this obviously, and if you go very slow from a stop, it doesnt do it either... am I correct? It is normally when you accelerate more than half throttle by the time it locks up.
Old 01-12-2005, 04:11 PM
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Yeah that sounds about right. I think it can easily be reproduced, but would have to figure out the trick exactly.
Old 01-12-2005, 05:55 PM
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I wouldn't consider locking up hard a bad thing.
Old 01-13-2005, 01:10 PM
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Yesterday I went cruising, it seems to be a random occurance. But yeah, I suppose that's a good thing.
Old 01-13-2005, 06:00 PM
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would that be due to a fairly high STR? i know the ST3500 only has something like a 1.6 though right? or is it 2.5-2.8 range?
Old 01-13-2005, 06:05 PM
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What gear are you in when the TC locks hard? I have a Midwest 3600/2.0 and it locks harder in 3rd than it does in 4th. I raised the lock-up speeds and locks nice and smooth in 3rd.
Old 01-13-2005, 07:52 PM
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I'm guessing 3rd...because 4th is overdrive. It's usually around 35-40 that it happens.
Old 01-13-2005, 10:40 PM
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I've been told that a firm lock up on most aftermarket higher stall TCs is normal. Especially in cases where the lockup mode on the trans is setup up to be either on and off not gradually on and gradually off.

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Old 01-14-2005, 07:18 AM
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that can be easily tuned out (pwm i believe) you just have to find the correct tables to adjust via hptuners/ls1 edit. i'd rather my tc lockup HARD then slip out of lockup like mine did. also the lockup points could play a role in this.




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