Cold shift..? 
Torque Converter Lockup Issues
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From: Fruitvale B.C.
Torque Converter Lockup Issues
Hey Recently I have been having some problems with my converter not locking up when it should be. It doesn't lock up in gears 1-3 at all no matter how hard I am on the throttle. In 4th it will only lockup when I'm at 3/4 to 7/8 throttle and even then it only happens every now and again. When it goes into OD it locks up right away most of the time... the only times it doesn't is right after I have started the truck... It stays unlocked through all the gears and then after about 3 miles of driving it will lock up (but only in OD) Do any of you guys have a reason why it would be doing this? The tranny was just rebuilt last year so I would think it should be good to go. It was running fine till about a month and a half ago and then it just randomly started giving me a hard time.
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From: Ellensburg, Washington
I don't think you understand what a locked convertor or an unlocked convertor is. If it isn't locking up then there would be no movement. The feeling would be as if you were in neutral. A locked convertor would is when there is no slip at all, the minute you mash the throttle to the floor the truck has no slip, shifts are firm and quick and there would be a lite jarring when you let off the throttle and fly back into it. I have had 4 trannies in my truck through my illustrious career of pursuing the 12's and when the convertor goes out it usually is the result of something else, like a clutch pack going out, low fluid, high temps, excessive addition of hp, etc.,
Cowboy Steve
Cowboy Steve
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From: Silver Lake Dunes, MI
Hey Recently I have been having some problems with my converter not locking up when it should be. It doesn't lock up in gears 1-3 at all no matter how hard I am on the throttle. In 4th it will only lockup when I'm at 3/4 to 7/8 throttle and even then it only happens every now and again. When it goes into OD it locks up right away most of the time... the only times it doesn't is right after I have started the truck... It stays unlocked through all the gears and then after about 3 miles of driving it will lock up (but only in OD) Do any of you guys have a reason why it would be doing this? The tranny was just rebuilt last year so I would think it should be good to go. It was running fine till about a month and a half ago and then it just randomly started giving me a hard time.
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Joined: Feb 2004
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From: Levittown
OD lamp flash?
I would scan the TFT. Possible short or out of range.
If the TFT is showing to cold you will get the cold shift schedule.
Cold schedule in some PCM codes does not allow TC lock until fluid is warmed up some.
Also scan the TC lock to see if PCM sent the sig and the trans ignored for it for other reasons.
It could be locked just slipping. It will not slip code unless it slips while in OD.
Bill
I would scan the TFT. Possible short or out of range.
If the TFT is showing to cold you will get the cold shift schedule.
Cold schedule in some PCM codes does not allow TC lock until fluid is warmed up some.
Also scan the TC lock to see if PCM sent the sig and the trans ignored for it for other reasons.
It could be locked just slipping. It will not slip code unless it slips while in OD.
Bill
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Post Fiend
Joined: Apr 2004
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From: Silver Lake Dunes, MI
Bill do you know if cold shiFt can be programmed out. I am going to be sending my chip to TW. I would love to get rid of it.
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Joined: Feb 2004
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From: Levittown
Its a catch 22. Do you rev the motor/trans higher to warm it quicker?
Or should you wait for fluid and metal temps to come up first.
It will play with the shift feel a bit with cold fluids in low temps.
Its not an issue with syn trans fluid.
I think the cold thing changed with the DPC-for splits.
The earliest pcm codes (year 97) i have found that will lock cold are e-series/splitshot. Then came the SD. They short shift cold.
Ricks the expert on this, he has done alot of testing fooling the PCM and TFT.
Bill
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will it help the cold shift?...
Postmaster
Joined: Feb 2004
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From: Levittown
Its more stable of a fluid.
Its not a when to shift its a how it feels shift.
The dino is slower to move and line pressure is higher in low temps.
The syn goes right to work in the cold temps.
Bill
Its not a when to shift its a how it feels shift.
The dino is slower to move and line pressure is higher in low temps.
The syn goes right to work in the cold temps.
Bill