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#1052913 - 08/14/17 03:14 AM How to tell when the torque converter locks up?  
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ChasUno Offline
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Bradenton, FL
Quick question.

How can I tell that my transmission engages the lock up torque converter? I can tell that it engages gears, and also goes into OD 4th (I can drop it down into 3rd with the shifter). Is there a tell tale sign when the TC lock up engages/ disengages?


1986 Monte Carlo SS

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#1052914 - 08/14/17 03:29 AM Re: How to tell when the torque converter locks up? [Re: ChasUno]  
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mmc427ss Online content
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Generally lockup occurs about 45 mph. To test, shifter in D, drive 50 mph, touch the brake pedal lightly, the engine rpm will increase about 400 rpm. Take your foot off the brake pedal, rpm decreases as the converter locks back up. Repeat, converter should unlock then lock back up seamlessly. Converter lockup only occurs when the trans is in 4th gear on a 200R.
Bob

#1052933 - 08/15/17 12:05 AM Re: How to tell when the torque converter locks up? [Re: ChasUno]  
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86ttop Online grandpa
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the engine temp needs to be about 170 degrees for the lockup to work as well.


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#1052934 - 08/15/17 02:01 AM Re: How to tell when the torque converter locks up? [Re: ChasUno]  
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ChasUno Offline
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Bradenton, FL
Thank you Bob and Leo, I was curious to know what the tell tale signs were that the converter was actually locking/ working. I didn't know whether mine was or not.

Bob, do you mean drive with the the shifter in the "D" position to the right of "N" (that looks like a "D" inside a circle), and not the "D" to the left of "2" (on the shift indicator)? I'm assuming that the "D" inside the circle allows the transmission to go into overdrive 4th.

I have yet to get round to repairing my tachometer, so I have no visual indications of what the engine revolutions are. I will try driving up to 50mph and then touching the brakes lightly as you said, and listen for a change in engine tone indicating rising revs as the TC lock up disengages.

Also Leo, good call on pointing out that the engine temp needs to be above 170 degrees for lockup to occur. Since flushing/ servicing/ replacing parts on my cooling system, it now gets up to an indicated 190 - 200 degrees and pretty much sits there. Assuming the gauge is somewhat accurate, the engine should be at the correct operating temperature for TC lock up (and other temp dependent components in the CCC).

Has anyone installed an indicator light/ LED that comes on when the TC lock up system is in operation?


Last edited by ChasUno; 08/15/17 02:02 AM.

1986 Monte Carlo SS

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#1052936 - 08/15/17 03:38 AM Re: How to tell when the torque converter locks up? [Re: ChasUno]  
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mmc427ss Online content
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It's been 15 gears since I had a D in my car, kinda forget what that looks like. But yes, D should allow all four gear, 4th being OD.
Even without a tach you will notice the rpm change. And yes with the CCC the ECM needs to be in closed loop.
Bob

#1052937 - 08/15/17 11:02 AM Re: How to tell when the torque converter locks up? [Re: mmc427ss]  
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LXXXIV SS Offline
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Originally Posted by mmc427ss
It's been 15 gears since I had a D in my car, kinda forget what that looks like. But yes, D should allow all four gear, 4th being OD.
Even without a tach you will notice the rpm change. And yes with the CCC the ECM needs to be in closed loop.
Bob


In my daily driver, "D" will shift through the gears 1, 2, and 3 but not allow overdrive. "D" in a circle will allow it to shift through the gears 1, 2, 3, and overdrive.

#1052941 - 08/15/17 11:45 AM Re: How to tell when the torque converter locks up? [Re: ChasUno]  
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It has to be in overdrive (4th gear, just to the right of N) for it to lock up.

I made one of these cables:
http://winaldl.joby.se/aldlcable.htm

And downloaded WinALDL to talk to the ECM with my laptop. With that, you can see when the ECM calls for lockup and narrow it down if you have a problem. IIRC, the lockup clutch is powered through the brake pedal, then the 4th gear pressure switch (easily replaced after removing the pan), and it is grounded through the ECM. So if you tap on the brake pedal enough to light up the tail lights, it cuts power to the clutch. Similarly, if you are not in 4th gear (or the switch is malfunctioning), it won't give power to the clutch, and if both of those switches close, the ECM decides when to ground (complete) the circuit. If all of that is working and you still don't have lockup, the common issue is the solenoid.

http://www.montecarloss.com/TCC_Solenoid.html

Last edited by SickSpeedMonte; 08/15/17 11:46 AM.
#1053049 - 08/23/17 04:12 AM Re: How to tell when the torque converter locks up? [Re: ChasUno]  
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ChasUno Offline
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Bradenton, FL
LXXXIV SS, thanks for confirming that the transmission needs to be in overdrive 'D' to engage the lock up clutch. That's what I suspected.

And SickspeedMonte, great information there! If I suspect that the clutch isn't engaging I may well try going down the route of making that cable and reading the ECM.

I'm still not sure if mine is engaging or not, though that's because I have not been out in the car much to test it. Next time I am taking it for a spin I will try and use the 50mph and touching the brakes technique (I assume I should use left foot braking so as to keep the accelerator constant). Hopefully it will all be working.


1986 Monte Carlo SS

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#1053051 - 08/23/17 04:21 PM Re: How to tell when the torque converter locks up? [Re: ChasUno]  
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tedgley Offline
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If you are using the technique Bob suggests (and it is exactly what I would have recommended, too), the effect will be more pronounced if you are going up a hill when you hit the brake. The rpm increase will be very noticeable then.l

#1053054 - 08/23/17 10:22 PM Re: How to tell when the torque converter locks up? [Re: ChasUno]  
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guitars Offline
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To me it feels like a 1/2 gear shift - very subtle decrease in RPM while accelerating with light throttle

#1053060 - 08/24/17 04:27 AM Re: How to tell when the torque converter locks up? [Re: tedgley]  
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ChasUno Offline
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Bradenton, FL
Originally Posted by tedgley
If you are using the technique Bob suggests (and it is exactly what I would have recommended, too), the effect will be more pronounced if you are going up a hill when you hit the brake. The rpm increase will be very noticeable then.l



Only problem with that technique down here in Florida, is that there aren't any hills!

lmao


1986 Monte Carlo SS

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#1053067 - 08/25/17 12:07 AM Re: How to tell when the torque converter locks up? [Re: ChasUno]  
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wxdude64 Offline
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Covington, VA
Originally Posted by ChasUno
Originally Posted by tedgley
If you are using the technique Bob suggests (and it is exactly what I would have recommended, too), the effect will be more pronounced if you are going up a hill when you hit the brake. The rpm increase will be very noticeable then.l



Only problem with that technique down here in Florida, is that there aren't any hills!

lmao

Yes, that is a slight problem......


87 Black/Tan Aerocoupe
#1053194 - 09/03/17 04:47 AM Re: How to tell when the torque converter locks up? [Re: ChasUno]  
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ChasUno Offline
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Bradenton, FL
Took my MC for spin the other day and tried the above technique. I noticed that at around 50mph or so, that it I have the throttle lightly open (as if maintaining a cruising speed) and I touch the brake pedal at the same time, I can't tell that the engine increases its revs but I can definitely feel it drop when I then release the brake pedal. I did this a few times and it did this fairly consistently. Also, does the car have to be doing below a certain speed for the torque converter to unlock? I tried the technique at interstate speeds (60mph and above) and it didn't appear to do anything.

Last edited by ChasUno; 09/03/17 04:48 AM.

1986 Monte Carlo SS

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#1053218 - 09/04/17 04:27 PM Re: How to tell when the torque converter locks up? [Re: ChasUno]  
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mmc427ss Online content
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The 200R4 has a 4th gear switch internally that allows lockup only in 4th. I assume when the trans downshifts to 3rd gear the lockup is disengaged. It's been 15 years since having a 200R, old guys forget stuff.
Bob

#1053450 - 09/18/17 11:35 PM Re: How to tell when the torque converter locks up? [Re: ChasUno]  
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JMonte7892 Offline
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Originally Posted by ChasUno
Took my MC for spin the other day and tried the above technique. I noticed that at around 50mph or so, that it I have the throttle lightly open (as if maintaining a cruising speed) and I touch the brake pedal at the same time, I can't tell that the engine increases its revs but I can definitely feel it drop when I then release the brake pedal. I did this a few times and it did this fairly consistently. Also, does the car have to be doing below a certain speed for the torque converter to unlock? I tried the technique at interstate speeds (60mph and above) and it didn't appear to do anything.


Been a couple of years but if i remember correctly mine would unlock below either 40 or 45mph.


1983 Monte Carlo Sport Coupe [sold]
1984 Monte Carlo Super Sport [deathmatch with a Santa Fe]
1985 Monte Carlo Sport Coupe [frame-off in progress]
#1053453 - 09/19/17 10:53 AM Re: How to tell when the torque converter locks up? [Re: ChasUno]  
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Chas - you have the Sunshine Skyway Bridge just a few clicks away. Now that might be the only reasonable hill in the whole state. :-)


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#1053577 - 09/25/17 01:08 AM Re: How to tell when the torque converter locks up? [Re: ChasUno]  
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ChasUno Offline
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Bradenton, FL
True that!

Then again, using the techniques mentioned earlier I have been able to identify the TCC engaging and disengaging. Saves me paying the toll on the Sunshine Skyway just to see if my TCC is working or not!


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