Torq Converter Question...
Thread Starter
Melting Slicks
Joined: Feb 1999
Posts: 2,473
Likes: 10
From: New Paltz, New York USA
Torq Converter Question...
I have a new crate motor in my 81. I have also removed the computer and because of this I had to replace my distributor and carburetor.
The lock up torque converter was being controlled by the old computer. My question is: Will there be any damage done to the transmission because the lock up is not working? I am thinking that it will only hurt my millage, but not sure. Thanks in advance.
The lock up torque converter was being controlled by the old computer. My question is: Will there be any damage done to the transmission because the lock up is not working? I am thinking that it will only hurt my millage, but not sure. Thanks in advance.
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,118
From: Crossville TN
You will not damage the transmission if the lockup function is not operational. You will get a bit poorer fuel mileage for both highway and suburban driving (in-city will likely be the same). You can hook up your computer again and have it only operate the lockup clutch, if you want. Or, you can hook up a switch with 12vdc to send to the lockup clutch when you want to use it. However, I would not recommend that last option, as it doesn't take into account the ability to 'cancel' the lockup function when braking, when climbing a hill, etc. The ECM that was on the car will handle all of these circumstances, as long as you have it wired properly and have not removed the brake switch associated with the lockup operation.
Thread Starter
Melting Slicks
Joined: Feb 1999
Posts: 2,473
Likes: 10
From: New Paltz, New York USA
You will not damage the transmission if the lockup function is not operational. You will get a bit poorer fuel mileage for both highway and suburban driving (in-city will likely be the same). You can hook up your computer again and have it only operate the lockup clutch, if you want. Or, you can hook up a switch with 12vdc to send to the lockup clutch when you want to use it. However, I would not recommend that last option, as it doesn't take into account the ability to 'cancel' the lockup function when braking, when climbing a hill, etc. The ECM that was on the car will handle all of these circumstances, as long as you have it wired properly and have not removed the brake switch associated with the lockup operation.
Melting Slicks
Joined: Apr 2000
Posts: 3,341
Likes: 6
With a 350C, the three speed w/lockup used in '80 and '81, it is OK to not use the lockup. The only penalty is the loss of fuel efficiency.
With a 700R4, the 4 speed overdrive w/lockup used in '82, leaving the lockup function disabled will result in horrific overheating of the transmission.
With a 700R4, the 4 speed overdrive w/lockup used in '82, leaving the lockup function disabled will result in horrific overheating of the transmission.
Drifting
Joined: Aug 2005
Posts: 1,682
Likes: 3
From: League City TX
Melting Slicks
Joined: Apr 2000
Posts: 3,341
Likes: 6
Disabling the converter lock-up function in a 350C was a trick to get around problems with the lock-up clutch in the converter. When the 700 came along, people that tried the same trick and were rewarded with a horribly overheated tranny. I mean so hot you couldn't put your hand on them. At that point a complete rebuild or replacement was the only option. Another converter was also needed.
Race Director
Joined: Apr 1999
Posts: 11,520
Likes: 13
From: CORVETTE 77 385 C.I. TEXAS
When I was talking to Mike Kurtz (high performance trans. specialist) about a blown built (not by Kurtz) TH2004R he mentioned the TH2004R could handle a non lockup converter much easier than the 700R4.
Here's something not normally mentioned.
"Also note that the GM 700R4 (4L60) transmission does not route fluid to the cooler unless the TCC is locked."
http://www.diy-efi.org/gmecm/papers/tcc.txt
"it does but it is not alot"
Chris
christoforos Kokkonis,general motors transmission specialist
www.ckperformance.com
Here's something not normally mentioned.
"Also note that the GM 700R4 (4L60) transmission does not route fluid to the cooler unless the TCC is locked."
http://www.diy-efi.org/gmecm/papers/tcc.txt
"it does but it is not alot"
Chris
christoforos Kokkonis,general motors transmission specialist
www.ckperformance.com
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