What's actually "beefed up" to your TH400?
01-23-2008, 12:08 AM
#1
What's actually "beefed up" to your TH400? I've got a TH400 that came out of my vette that's getting an LS1 swap and I'm thinking of tearing it down myself and rebuilding it to handle the 800rwhp in my GTO. I've been trying to search but not finding much luck on what's actually done to a high performance TH400 internally. Any help? I know the trannys are pretty beefy as is so many just a hipo rebuild with better clutches and a FMVB will do it? I don't want a trans brake,
Thanks, looking forward to some answers!
-Adam
Thanks, looking forward to some answers!
-Adam
Last edited by HydroStream6; 01-23-2008 at 12:15 AM.
01-23-2008, 09:41 AM
#2
Hello Adam,
Very good question here. There are several different upgrades for a TH400 in a Performance application.
The valve body you mentioned will retain engine braking as opposed to a unit that has a Brake.
We always cut the Direct piston on our lathe in order to allow us to install up to 6 clutches.
We install hardened Input shafts in anything over 500 h/p... that's just good insurance.
They really aren't that expensive as compared to having to go through the hassle of a removal for repair down the road.
We like to see Waffled clutches in the Forward clutch pack.
We run a 34 element sprag instead of the factory spring and roller set up. This requires the replacement of the Direct drum if it is a late model unit.
In our Race applications we like to run Kevlar bands. In street / strip mild application we would run a High Energy type material on the bands.
From there we will make some custom oiling modifications.
If you would like to discuss some options don't hesitate to give me a call.
Hope that info helps.
g
Very good question here. There are several different upgrades for a TH400 in a Performance application.
The valve body you mentioned will retain engine braking as opposed to a unit that has a Brake.
We always cut the Direct piston on our lathe in order to allow us to install up to 6 clutches.
We install hardened Input shafts in anything over 500 h/p... that's just good insurance.
They really aren't that expensive as compared to having to go through the hassle of a removal for repair down the road.
We like to see Waffled clutches in the Forward clutch pack.
We run a 34 element sprag instead of the factory spring and roller set up. This requires the replacement of the Direct drum if it is a late model unit.
In our Race applications we like to run Kevlar bands. In street / strip mild application we would run a High Energy type material on the bands.
From there we will make some custom oiling modifications.
If you would like to discuss some options don't hesitate to give me a call.
Hope that info helps.
g
01-23-2008, 12:35 PM
#4
Hello Adam,
Very good question here. There are several different upgrades for a TH400 in a Performance application.
The valve body you mentioned will retain engine braking as opposed to a unit that has a Brake.
We always cut the Direct piston on our lathe in order to allow us to install up to 6 clutches.
We install hardened Input shafts in anything over 500 h/p... that's just good insurance.
They really aren't that expensive as compared to having to go through the hassle of a removal for repair down the road.
We like to see Waffled clutches in the Forward clutch pack.
We run a 34 element sprag instead of the factory spring and roller set up. This requires the replacement of the Direct drum if it is a late model unit.
In our Race applications we like to run Kevlar bands. In street / strip mild application we would run a High Energy type material on the bands.
From there we will make some custom oiling modifications.
If you would like to discuss some options don't hesitate to give me a call.
Hope that info helps.
g
Very good question here. There are several different upgrades for a TH400 in a Performance application.
The valve body you mentioned will retain engine braking as opposed to a unit that has a Brake.
We always cut the Direct piston on our lathe in order to allow us to install up to 6 clutches.
We install hardened Input shafts in anything over 500 h/p... that's just good insurance.
They really aren't that expensive as compared to having to go through the hassle of a removal for repair down the road.
We like to see Waffled clutches in the Forward clutch pack.
We run a 34 element sprag instead of the factory spring and roller set up. This requires the replacement of the Direct drum if it is a late model unit.
In our Race applications we like to run Kevlar bands. In street / strip mild application we would run a High Energy type material on the bands.
From there we will make some custom oiling modifications.
If you would like to discuss some options don't hesitate to give me a call.
Hope that info helps.
g
01-23-2008, 06:29 PM
#5
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What about the sprag material, Aluminum vs steel? What kind of RPM can each handle? I noticed that being an expensive option I did and I don't remeber why, lol.
01-23-2008, 06:39 PM
#6
Dan the sprag is a component that takes quite a punishment. It cannot be made of aluminum and survive.
The 400 can take all you can throw at it if properly built. 9,000 rpm is not too big of a problem if it has the proper drums and is set up for it. I don't recommend that with the heavy factory drums.
The sprag can be an expensive option if you need to buy the drum, the race and the sprag. I think ATI sells their Center Support and drum assy for like $1,100.00. But I would not worry about the factory parts in any car running as low as 9.50's.
Just don't go kicking it into neutral through the traps... real bad things happens when you do!
g
The 400 can take all you can throw at it if properly built. 9,000 rpm is not too big of a problem if it has the proper drums and is set up for it. I don't recommend that with the heavy factory drums.
The sprag can be an expensive option if you need to buy the drum, the race and the sprag. I think ATI sells their Center Support and drum assy for like $1,100.00. But I would not worry about the factory parts in any car running as low as 9.50's.
Just don't go kicking it into neutral through the traps... real bad things happens when you do!
g
01-23-2008, 06:47 PM
#7
good info ratchthed, i am due for a freshining up in my th400 in my LeMans. not to hijack this thread, but i was woundering if there are other issues that arise from improper, but common, treatment of the th400 at the track. i have only heard of the "don't shift into nuetral at the lights" and "during burnout, shift quickly from 1 to 2 but don't burn in 3rd" or something to that nature. do you have any other tips?
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01-23-2008, 07:03 PM
#8
Only other thing I would add is if your transmission is equipped with a Brake and you are on the Brake at a high rpm do not simply let off the throttle as you could damage the converter turbine or converter sprag.
If you have to abort the run, release the Brake and then the throttle.
g
If you have to abort the run, release the Brake and then the throttle.
g
01-23-2008, 07:38 PM
#9
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Dan the sprag is a component that takes quite a punishment. It cannot be made of aluminum and survive.
The 400 can take all you can throw at it if properly built. 9,000 rpm is not too big of a problem if it has the proper drums and is set up for it. I don't recommend that with the heavy factory drums.
The sprag can be an expensive option if you need to buy the drum, the race and the sprag. I think ATI sells their Center Support and drum assy for like $1,100.00. But I would not worry about the factory parts in any car running as low as 9.50's.
Just don't go kicking it into neutral through the traps... real bad things happens when you do!
g
The 400 can take all you can throw at it if properly built. 9,000 rpm is not too big of a problem if it has the proper drums and is set up for it. I don't recommend that with the heavy factory drums.
The sprag can be an expensive option if you need to buy the drum, the race and the sprag. I think ATI sells their Center Support and drum assy for like $1,100.00. But I would not worry about the factory parts in any car running as low as 9.50's.
Just don't go kicking it into neutral through the traps... real bad things happens when you do!
g
.Dan
01-24-2008, 05:53 AM
#11
I suggest running Teflon rings in these units. The steel rings seem to destroy
hard parts with elevated pressures. Also as Gil mentioned adding clutches is a
good idea. I will add a clutch to the intermediate clutch. Also the
intermediate band can be upgraded to a late 4l80e band. It will require that
you change the servo because the pin is a different length. Just a heads up
you can also use a direct drum from a 4l80e. It will already have the sprag
you are looking for and it will accept 6 clutches while allowing you to use a
bonded piston. No machining required.
Good luck with your build. Vince
hard parts with elevated pressures. Also as Gil mentioned adding clutches is a
good idea. I will add a clutch to the intermediate clutch. Also the
intermediate band can be upgraded to a late 4l80e band. It will require that
you change the servo because the pin is a different length. Just a heads up
you can also use a direct drum from a 4l80e. It will already have the sprag
you are looking for and it will accept 6 clutches while allowing you to use a
bonded piston. No machining required.
Good luck with your build. Vince 