Torque Converter lock-up
Thread Starter
Racer
Joined: Nov 2011
Posts: 274
Likes: 12
From: Louisburg NC
Torque Converter lock-up
I bought my 'vette a few weeks ago. '94 with 100K miles.
The TC seems to have a lock-up problem at speed. Sometimes, not always, when cruising at highway speed (60-75 mph) with the cruise control on the TC locks and unlocks randomly and often. It seems to stay unlocked most of the time, however.
Any ideas where I should start looking?
The TC seems to have a lock-up problem at speed. Sometimes, not always, when cruising at highway speed (60-75 mph) with the cruise control on the TC locks and unlocks randomly and often. It seems to stay unlocked most of the time, however.
Any ideas where I should start looking?
Drifting
Joined: Dec 2007
Posts: 1,647
Likes: 4
From: Argillite KY
Where I'd start looking is at the things that control the lockup. Check your brake light switch, do the resistance check on the throttle position sensor and of course the engine coolant temp sensor. I have seen the most failures from a faulty coolant sensor than anything though. There are others but that is a good place for you and your ohm meter to start.
Thread Starter
Racer
Joined: Nov 2011
Posts: 274
Likes: 12
From: Louisburg NC
I like to leave the coolant temp turned on on the LCD. On my way home from work this afternoon, I was stopped at a light and happened to look down at the LCD and it said 142 degrees. After sitting in traffic for 45 minutes I new that was wrong. Then I noticed the "service engine soon" light. Then the temp reading started jumping around from 142 to 214 to 180sumpthin'. The engine started running funny. Kinda freaked me out, this being my 1st 'vette and all. The light turned green and I went and every thing settled down. Check light went out and the engine started running right.
You think that might be related to the coolant temp sensor?
Last edited by oilyfishhead; Nov 14, 2011 at 10:28 PM.
Le Mans Master
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From: Australia
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Thread Starter
Racer
Joined: Nov 2011
Posts: 274
Likes: 12
From: Louisburg NC
I'm not much on chemical additives. I figure if they were necessary, the factory would add them.
This weekend I added a quart of Lucas Transmission stuff. (after removing a quart of fluid from the trans, of course.) I'll be dammed if it didn't fix the lock-up problem. I made my usual Sunday afternoon run from NC to VA (250 miles) and it worked perfectly. The TC locked up when it was supposed to and unlocked when it was supposed to. I'm amazed.
This weekend I added a quart of Lucas Transmission stuff. (after removing a quart of fluid from the trans, of course.) I'll be dammed if it didn't fix the lock-up problem. I made my usual Sunday afternoon run from NC to VA (250 miles) and it worked perfectly. The TC locked up when it was supposed to and unlocked when it was supposed to. I'm amazed.
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Instructor
Joined: Nov 2011
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the lucas works that and lube gard are the only additives i use in the shop i had a transam doing the same thing locking and un locking it was the tps it would do it intermittantlly most likely is the torque converter valve is worn in the valve body
Team Owner
Joined: Sep 2003
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From: Freedom is never more than one generation away from extinction.
St. Jude '03 thru '24
Race Director
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Le Mans Master
Joined: Jan 2006
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From: Orlando FL
On the brake pedal there is a triple switch assembly. Three different switches with different circuits. One is for the brake light, cruise and lock up. A lot of cruise problems are caused be a poor contact (high resistance) on the dedicated switch. The lock up portion may have a similar problem with the contacts.
Although the whole switch assembly can be replaced, I have repaired them. The contacts for all three switches can be removed easily, cleaned up and spring tension re-adjusted. May have to adjust switch assembly after installed.
Although the whole switch assembly can be replaced, I have repaired them. The contacts for all three switches can be removed easily, cleaned up and spring tension re-adjusted. May have to adjust switch assembly after installed.
Heel & Toe
Joined: Mar 2011
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Interesting!?!
I like to leave the coolant temp turned on on the LCD. On my way home from work this afternoon, I was stopped at a light and happened to look down at the LCD and it said 142 degrees. After sitting in traffic for 45 minutes I new that was wrong. Then I noticed the "service engine soon" light. Then the temp reading started jumping around from 142 to 214 to 180sumpthin'. The engine started running funny. Kinda freaked me out, this being my 1st 'vette and all. The light turned green and I went and every thing settled down. Check light went out and the engine started running right.
You think that might be related to the coolant temp sensor?
I like to leave the coolant temp turned on on the LCD. On my way home from work this afternoon, I was stopped at a light and happened to look down at the LCD and it said 142 degrees. After sitting in traffic for 45 minutes I new that was wrong. Then I noticed the "service engine soon" light. Then the temp reading started jumping around from 142 to 214 to 180sumpthin'. The engine started running funny. Kinda freaked me out, this being my 1st 'vette and all. The light turned green and I went and every thing settled down. Check light went out and the engine started running right.
You think that might be related to the coolant temp sensor?
hit 142 degrees and stayed - it was also a failing coolant temp sensor. The part of plug had broken off and the contacts where just tangling there. I guess it got hot or something.
Race Director
Joined: Apr 2002
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From: Anaheim CA
The torque converter clutch solenoid is in the pump. Not connected to the valve body at all.
I would suspect a problem with the switch on the brake pedal. They are easy to adjust and you can do it without tools (except the ones required to take the kick panel off...).
I would suspect a problem with the switch on the brake pedal. They are easy to adjust and you can do it without tools (except the ones required to take the kick panel off...).
