lock-up converter in a TH 400 - Chevelle Tech
Transmission & Driveline Transmissions and Differentials

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post #1 of 6 (permalink) Old Apr 10th, 03, 2:54 AM Thread Starter
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Does anyone have any experience with a lock-up converter in a TH 400? If so, what is the process to adding this to a trans. not currently set up for lock-up? Also, where can you find the lock-up converters for the TH 400 and how is the lock-up switch supposed to be set up? Thanks for any help.

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post #2 of 6 (permalink) Old Apr 10th, 03, 7:25 AM
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I don't think it can be done, even the overdrive 4L80E (which might be considered the later model version of a th400) doesn't have lock up.
There are switch pitch th400's that use a converter with two stall speeds and a switch in the trans to change between the two.
Maybe one of the transmission guys here can provide some more information.

1975 Nova w/1966 427/manual th400, 11.8 @ 115mph.
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post #3 of 6 (permalink) Old Apr 10th, 03, 7:33 AM
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John, I have not seen this done, as Jay indicated. The switch-pitch deal was used by Buick-Olds-Caddy(?) a long time ago. It had a setup that changed the stator fin angle. It was not a setup capable of withstanding much power though, it would blow the fins out of the stator if you made any power at all. I have seen many Powerglide race trannies that have been made into lockups, especially for ultra-high HP heavier car applications. But, you are looking at over $7K for a complete setup! Using a lockup in a TH400 sounds like you are maybe after some cruising economy, and not so much performance? I would look to one of the factory lockup trannies, there are quite a few HD parts now made for them. I sell TCI and JW, you can see the TCI stuff at www.tciauto.com, they have a decent website. JW has a site, but not much is on there.
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post #4 of 6 (permalink) Old May 17th, 03, 4:51 AM
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Actually there is a lockup conversion that was developed about 2 years ago. It is made by a company in New York, I think, I could look it up for you if you'd like. It was developed for racing, and will handle a lot of HP (800 - 900). The only downside is that it runs in the neighborhood of about $2,700 for the parts to convert it (including the convertor), then you essentially have to rebuild the tranny to install everything (another $400 or so, depending on your tranny shop) (unless you can do your own tranny rebuilds). It was intended to lock up at the end of the 1/4 mile so you can get improved efficiency and better MPH.

The switch-pitch is a much better way to go in my opinion. You will still have to remove the tranny and essentially do a whole rebuild (the front pump has to be replaced and you have to putz with some other internals), but is much cheaper and very strong- you can buy a conversion kit from Kenne-Bell (under $200 not including convertor), and a convertor for about $450 (www.trisheld.com. So if you add a bench rebuild from your local shop, you are in it for about $1,000. It is a wicked setup- in my daily driver, I get fabulous gas mileage and still occasionally can put about 750HP into it (although the convertor manufacturer recommends a limit of about 600HP). My convertor gives about 1800 low stall and 3000 high stall- works great for both highway cruising and for racing.

I gotta tell you, I love my switch pitch! I don't know why they aren't more popular. I can tell you, I'll never get rid of mine!

If you want more info on where to get the convertor, shoot me an email at bobcATgnttype.org.

-Bob Cunningham
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post #5 of 6 (permalink) Old May 17th, 03, 8:29 PM
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Not New York, but Tennesse: http://www.converter.com/vigilante.htm

I'm not sure where these come from, but http://www.converter.cc/C-5conversion.htm also offers lock up TH400 converters

FLP Trans has them in the works as well.

Old school be damned - you will be seeing more and more high hp cars going this route.


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post #6 of 6 (permalink) Old May 17th, 03, 8:52 PM
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I was under the understanding that Yank has what he called a posi lockup converter, the clutched locked by the torque, the more torque the harder it held. Call him to get the details.


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PowerGlide, 5000 stall converter. 8.70@154 MPH

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