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Old 10th June 2013, 01:01   #1
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Default Chevrolet Captiva : Activate Lock Up Clutch at 20 kph?

Hi Guys!

Well, I have a Chevrolet Captiva, 2010 AWD AT.

The 5 speed automatic is one of the worst Auto's I've ever driven! The lock up clutch gets active above 130 kmph only. Below that its ridiculous. Just keeps revving no matter which gear it is in. Since Dad was using the car, I dint bother too much. Now that it's come to me, I cant take it. I need to modify the shift logic so that the Lock up clutch ( the one that basically bypasses the TC comes in Place as soon as I cross 20 kmph. irrespective of my gear position.

I know a little, I'm gonna dig in more info on this. Experts, Please help me with this.

Thanks

I'll keep you'all posted.

Drive Safe
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Old 10th June 2013, 21:23   #2
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Default Re: Chevrolet Captiva : Activate Lock Up Clutch at 20 kph?

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Originally Posted by stuntfreak View Post
The 5 speed automatic is one of the worst Auto's I've ever driven! The lock up clutch gets active above 130 kmph only. Below that its ridiculous. Just keeps revving no matter which gear it is in. Since Dad was using the car, I dint bother too much. Now that it's come to me, I cant take it. I need to modify the shift logic so that the Lock up clutch ( the one that basically bypasses the TC comes in Place as soon as I cross 20 kmph. irrespective of my gear position.
Some points you should note:

1. The lock up clutch works on centrifugal pressure of the torque converter and not on shift logic so alteration of the shift logic will not get the lock up clutch to activate earlier.

2. Now the complex part: You will have to manually put in circuits that will force the fluid to drain out at lower speeds this is a very complex procedure and is not quite the same as reprogramming the software.

3. The downside of early activation of the lock up clutch with lower centrifugal pressure will be loss of torque at lower speeds which will have its effect on performance.

4. The lock up clutch is not designed to take heavy loads such as a fully loaded car starting off and picking up speed.

5. I would advise that you stick with the original unless you have a highly experienced garage to do this and are prepared to put up with the other downsides such as loss of torque at lower engine speeds and increased chances of mechanical failure.
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Old 10th June 2013, 21:39   #3
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Quote:
Originally Posted by VeyronSuperSprt View Post

Some points you should note:

1. The lock up clutch works on centrifugal pressure of the torque converter and not on shift logic so alteration of the shift logic will not get the lock up clutch to activate earlier.

2. Now the complex part: You will have to manually put in circuits that will force the fluid to drain out at lower speeds this is a very complex procedure and is not quite the same as reprogramming the software.

3. The downside of early activation of the lock up clutch with lower centrifugal pressure will be loss of torque at lower speeds which will have its effect on performance.

4. The lock up clutch is not designed to take heavy loads such as a fully loaded car starting off and picking up speed.

5. I would advise that you stick with the original unless you have a highly experienced garage to do this and are prepared to put up with the other downsides such as loss of torque at lower engine speeds and increased chances of mechanical failure.
Hello, and thanks for your valuable input. Can't I swap out the tc with another one that allows the same? Also yes I do have a completely equipped place to work on cars. Just not worked on AT vehicles (on the transmission side)


And if it works on centrifugal pressure, why does is not work at higher revs in lower gears? Is it located in the input shaft? The other AT cars that I have do lock up much much quicker and it feels good.
Thanks.
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Old 10th June 2013, 22:29   #4
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Default Re: Chevrolet Captiva : Activate Lock Up Clutch at 20 kph?

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The other AT cars that I have do lock up much much quicker and it feels good.
Thanks.
How would you know when it is locked?
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Old 10th June 2013, 22:42   #5
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Default Re: Chevrolet Captiva : Activate Lock Up Clutch at 20 kph?

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How would you know when it is locked?
Just look at the tachometer..

In the captiva, whenever I accelerate, no matter what speed I am below 130 kmph, no matter which gear I am in (keep it in one gear - manually selected through the manumatic / tiptronic funtion), when I accelerate, the RPM difference before throttle and after throttle is 2000 RPM!!!! So basically when I'm in D mode, and I accelerate, my RPM stays up at 4k (Diesel vehicle), where my Turbo's range is over, and it keeps shifting as my speed increases. Even If I manually shift it to the next gear, I can feel the drop in torque (Shift happens), but the RPM Still stays where it is.

Now in all my other auto cars (They have a std AT. No DCT or AMT), its much better. For example, in my Camary, 2005, 4 speed AT, no matter which Gear I am in, when I accelerate, the RPM difference is just 200. And above 3200 - 3500, the lock up comes on as you can see the RPM Not drop at all (wrt speed) once you let go off the throttle. When you accelerate above that RPM, the RPM Diff is negligible. Thus the lock up has come on.

And so on..

Thanks
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Old 10th June 2013, 22:44   #6
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Default Re: Chevrolet Captiva : Activate Lock Up Clutch at 20 kph?

You can go for a Petes remap.They do have remaps for cruze automatic, I guess your captiva is having the same engine as cruze. I have driven the remapped cruze automatic. It has improved the car a lot (performance )
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Old 11th June 2013, 05:54   #7
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Default Re: Chevrolet Captiva : Activate Lock Up Clutch at 20 kph?

Quote:
Originally Posted by stuntfreak View Post
Hello, and thanks for your valuable input. Can't I swap out the tc with another one that allows the same? Also yes I do have a completely equipped place to work on cars. Just not worked on AT vehicles (on the transmission side)


And if it works on centrifugal pressure, why does is not work at higher revs in lower gears? Is it located in the input shaft? The other AT cars that I have do lock up much much quicker and it feels good.
Thanks.
Torque convertors can't just be swapped as it involves a lot of complex calculations as it executes very critical functions including it's ability to handle the various stresses. Lock up clutches work on the speed of the output shaft so as to be active at higher speeds. (medium to higher speeds depending on make of car). Especially as they cannot handle the initial (lug) loads. Even so, a difference of 2000 rpm is on the high side. You might want to have your AT checked/serviced.
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Old 11th June 2013, 08:05   #8
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Default Re: Chevrolet Captiva : Activate Lock Up Clutch at 20 kph?

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Originally Posted by VeyronSuperSprt View Post
Some points you should note:

1. The lock up clutch works on centrifugal pressure of the torque converter and not on shift logic so alteration of the shift logic will not get the lock up clutch to activate earlier.
Maybe back in the day. Lockup is controlled by the TCM directly using electro-hydraulically via the valve body. (as are other clutches)

Last edited by Mpower : 11th June 2013 at 08:06.
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Old 11th June 2013, 08:45   #9
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Default Re: Chevrolet Captiva : Activate Lock Up Clutch at 20 kph?

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Originally Posted by Mpower View Post
Lockup is controlled by the TCM directly using electro-hydraulically via the valve body. (as are other clutches)
That is the activation. The operation is as mentioned.
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Old 11th June 2013, 09:23   #10
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Quote:
Originally Posted by Mpower View Post
Maybe back in the day. Lockup is controlled by the TCM directly using electro-hydraulically via the valve body. (as are other clutches)
I'm gonna dig deeper and see what I find. I think the tcm can engage the clutch.

Thanks.
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Old 11th June 2013, 09:37   #11
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Default Re: Chevrolet Captiva : Activate Lock Up Clutch at 20 kph?

Centrifugal pressure is used to keep the lock-up clutch activated.
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