Lockup torque converter ?
Safety Car
Joined: Oct 2004
Posts: 3,927
Likes: 740
From: Youngstown Ohio
Ok, enough debate here. You know how lockup works, but it seems like you were saying it completely negates the converter, making it act totally like a clutch throughout its RPM range.......and it doesn't. Obviously, lockup is not for you. Also, the OP will decide if it's worth it or not.........just giving him some info. Bye.
Burning Brakes
Joined: Sep 2019
Posts: 923
Likes: 155
From: North Port, FL
The lockup converter is operated by a piston in the 700R4 trans, that is activated by an electrical current. You can run a wire to put a $2 toggle switch and turn it off and on at will or leave it on for constant use. Your choice. You can also buy a module to use it as well
Last edited by 0311 jarhead; Sep 15, 2021 at 01:34 AM.
Le Mans Master
Joined: Oct 2010
Posts: 6,952
Likes: 858
From: melbourne florida
2023 C3 of the Year Finalist - Modified
The lockup converter is operated by a piston in the 700R4 trans, that is activated by an electrical current. You can run a wire to put a $2 toggle switch and turn it off and on at will or leave it on for constant use. Your choice. You can also buy a module to use it as well
Team Owner
Joined: Apr 1999
Posts: 21,953
Likes: 1,445
From: Reno Nevada
2024 C3 of the Year Finalist- Modified
It looks like you already got the answer and them some! 
but NO th400 doesn't come with the ability to use a lockup style TC. Which is not a big deal if you install a highly efficient 9.5 inch vigilante TC. The problem with the 4 speed over drives like th700R4 and th200R4 is that in stock form they are very weak and poorly designed. Gear spacing is bad on the 700R4. I bought the brand new 450 hp Big block TQ handling TCI and they both broke in a mater of days with my little 350 ci. so I bought the best racing 700R4 and the best 9.5 inch TC with the 5 lockup clutches for big power.
The problem even with a 26 vane higher pressure pump and 5 lockup clutches is that at some point even they fail because they have a maximum friction holding point. Mine failed with a 650 hp 427 going to WOT in lockup somewhere way above 150 mph. The air wall is like a dyno 100% loading.
Well anyway I drove around with that highly efficient 9.5 inch for about 2 years without the lockup working. The difference is cruising down a level highway at 70 mph is a hardly any different in rpm than lockup or no lockup.
So I'm against the expense of negligible if any increase in gas mileage with a OD lock up tranny. Actually my MPG went down going to a 700R4. The problem was hopped up 700's use 25 more HP than a hopped up th350. th400 uses about 25 more hp than a th350.
PRECISION INDUSTRIES Vigilante Torque Converter (GM) [] (coloradospeed.com)
but NO th400 doesn't come with the ability to use a lockup style TC. Which is not a big deal if you install a highly efficient 9.5 inch vigilante TC. The problem with the 4 speed over drives like th700R4 and th200R4 is that in stock form they are very weak and poorly designed. Gear spacing is bad on the 700R4. I bought the brand new 450 hp Big block TQ handling TCI and they both broke in a mater of days with my little 350 ci. so I bought the best racing 700R4 and the best 9.5 inch TC with the 5 lockup clutches for big power.The problem even with a 26 vane higher pressure pump and 5 lockup clutches is that at some point even they fail because they have a maximum friction holding point. Mine failed with a 650 hp 427 going to WOT in lockup somewhere way above 150 mph. The air wall is like a dyno 100% loading.
Well anyway I drove around with that highly efficient 9.5 inch for about 2 years without the lockup working. The difference is cruising down a level highway at 70 mph is a hardly any different in rpm than lockup or no lockup.
So I'm against the expense of negligible if any increase in gas mileage with a OD lock up tranny. Actually my MPG went down going to a 700R4. The problem was hopped up 700's use 25 more HP than a hopped up th350. th400 uses about 25 more hp than a th350.
PRECISION INDUSTRIES Vigilante Torque Converter (GM) [] (coloradospeed.com)
Last edited by gkull; Sep 15, 2021 at 12:32 PM.
