Torgue Convertor questions?

gm280

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Jun 26, 2011
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Has anybody ever had a torque converter go bad in their vehicle? And if so, what were the symptoms? I am thinking I may have a lockup torque converter going bad but haven't convinced myself yet. I need other people's experiences to make that assumption. It has 175,000 miles on the '98 Blazer 4.3 V6 vehicle and I am getting what feels like a bucking feeling that seems like misfiring, but there are no codes showing that. :noidea: :help:
 

Grub54891

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Jun 17, 2012
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If it's bucking when you are coming to a stop, yeah it could be the converter. They get stuck in lockup mode and kill the motor sometimes. A shop I worked at would unhook something to prevent it from going in to lockup mode and it would be fine, just would not go in to lockup, witch increased engine rpm's, thus reducing fuel mileage. These cars were older, but I don't know what he did to do it.
 

gm280

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If it's bucking when you are coming to a stop, yeah it could be the converter. They get stuck in lockup mode and kill the motor sometimes. A shop I worked at would unhook something to prevent it from going in to lockup mode and it would be fine, just would not go in to lockup, witch increased engine rpm's, thus reducing fuel mileage. These cars were older, but I don't know what he did to do it.

No it doesn't buck while stopping or stalling the engine either. I only get that feeling around 40 to 50 MPH. It almost feels like engine missing pretty badly and I know that the engine isn't missing because it would certainly throw a code for misfire. I actually had such a code when the ignition was misfiring one time way before all this. So the misfiring feeling has to be something else and not engine performance. And the torque converter seemed likely but I really don't know. I guess it is telling me to start looking for a replacement SUV. :noidea:
 

bassman284

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Jun 24, 2006
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Sounds exactly like what I had in my 97 Grand Cherokee which turned out to be the lockup slipping. Combination of damage and wear apparently. I think it cost me about 6 or 7 hundred to fix it about 8 years ago. I was also around 170k miles and towed a boat with it.
 

G_Hipster

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Sep 24, 2016
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4l60e trans usually shifts to o/d at 45 mph. Sounds like it is kicking in and out of o/d. At 175k you have received a better service life than most if the trans has never been into and you tow with it. There is a selonoid in the trans that controls the o/d lock up. It could be that.
 
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gm280

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4l60e trans usually shifts to o/d at 45 mph. Sounds like it is kicking in and out of o/d. At 175k you have received a better service life than most if the trans has never been into and you tow with it. There is a selonoid in the trans that controls the o/d lock up. It could be that.

I'd like to thank Grub, bassman and G_Hipster for the replies. Today I tried something and it didn't seem to change so I am now wondering if it is torque converter or not. When I was running at about 45-50 MPH I again felt like it was surging (very minor though) and once I stopped again, I selected non-overdrive. But when I reached that same speed I still could feel it. So knowing the O/D option was not used, I figured the O/D lock up was out of the equation now. I guess it still could be, but I am thinking everything possible now.

As for the 4L60E transmission, I know all about then very well. I did have to rebuild that transmission because of the Sun Shell Gear stripping. So I replaced it with the "Beast". The beast is an after market replacement for the weak GM sun shell gear and it does fix them from stripping. And at that time I replaced all the steels and clutches and seals throughout the entire transmission. And the steels, clutches and seals were not bad, but since I had the transmission down, I rebuilt everything. I mean the total rebuild kit was a mere just over a $100 dollars, why not. That was many years ago. Actually I've rebuild quite a few of them for other people as well. Not really that hard. In fact any iboater on these forums could rebuilt a transmission easily.

I have a few new parts for the ignition system to replace and once I get everything finished,we will see if that skipping surging effect is still there. It is so subtle, my wife can't feel the vehicle doing anything. But usually the driver can. JMHO.
 

G_Hipster

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Sep 24, 2016
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Shoulda put a vette boost valve and pulled the check ball from the input shaft for a more solid lock up apply. Been through a few myself. Verters are not the place to try and save money and the dime store rebuilds can have issues with the lock up frictions.
 

dan t.

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Feb 28, 2008
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1,131
Sounds like torque shudder, to check it get up to 60 mph on a flat road and lightly push the brake pedal, this will make the torque unlock, try it a few times to be sure. If it is torque shudder it can usually be cured by dropping the pan and changing the oil and filter and adding a bottle of Lubegard. Good luck.
 
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