[6D6GOAT]

I have decided to build a TH400 to put behind my turbo'd 467
i plan to run a 4l80E direct drum and 34 element sprag, torrington bearings to replace thrust washers, red altos etc... i was going to do the internal dual feed mod as described by Jakes performace (thank you) and modifying the 1-2 valve for manual control.

my questions are..
should i install a torque converter feed restrictor? and if so what size hole?

and i read on anther build that if you use a 34 element sprag then you have to REMOVE the 1-2 check ball??? should it stay or go?

[chrisp]

Talk to member half inch stud , he is a turbo 400 expert .

[Cliff R]

There are no negatives that I know of by restricting the feed hole, it is well described in our book.

The "home brew" double feed works fine. I still like to purchase the Transgo kit, makes double feeding pretty easy, and you get the better springs for the direct drum, and KILLER strong snap ring for the intermediate backing plate in the case. Their kit also provides the orange pressure regulator spring, which I use here for most TH400 builds.

If you follow Jake's instructions from the website, be aware that separator plate hole sizes can have a HUGE impact on shift firmness, especially if you are disabling the accumulator(s), which is also mentioned. I would be very conservative with plate hole sizes if you go that route.

There is also no benefits to buying "special" high performance frictions or steel plates, unless you are trying to build high capacity drums using various combinations with thinner materials. The stock Raybestos or Borg Warner stuff is fine, even for big power levels, and a LOT less expensive. I've actually been using a lot of the later "high energy" stock type frictions in recent years, and highly recommend the 4L80E drum, molded apply piston, sprag, and spiral lock ring to keep it in place.........Cliff

[Schurkey]

Originally Posted by 6D6GOAT

and i read on anther build that if you use a 34 element sprag then you have to REMOVE the 1-2 check ball??? should it stay or go?

I have no idea why the 1-2 check ball would have any relation to the direct sprag.

[70 bird]

Vic I would restrict the converter feed, I used .150 and it seemed to work well with no converter stall change.

[Half-Inch Stud]

don't mess with the 1-2 shift valve; such a regretful modification.

Sounds like you got instructions.

[6D6GOAT]

Cliff... good to know about the clutches...unfortunately i have already spent the money on the red alto kit and yes it was expensive. As for Jakes mods, i will probably not even drill out anything on the separator plate for now. as for the direct drum springs i thought that was for high RPMs. this motor isnt going to be spinning past 5500 so i am hoping that wont be a problem. I did buy your book and have been skipping around as i read it. i must have skipped over your page on the torque converter restriction. but i see it now on page 94.

Schurkey, yea that seemed odd but i just want to make sure. here is a link to that build. He mentioned that towards the bottom where you see the valve body separator plate pics.

http://www.crankshaftcoalition.com/w...0_rebuild_tech

70 Bird. whats up dude? yea, i think that is what i am going to go with.

HIS I read your disgust with the 1-2 mod in other posts while researching.

one more question... i just got my 4L80E direct drum in the mail today. it has the spiral lock but looks to have a steel apply piston. where is a good source to get the molded apply piston and i see an aluminum one on ebay. Are those ok?

thanks again for the replies!

[Half-Inch Stud]

Check, does the the 4L80 steel apply piston for the "permanent rubber" lipseals.

[6D6GOAT]

HIS I can check it out in a bit. What are the pros and cons? If it is
Molded is that good or bad?

[6D6GOAT]

Just checked it. It is a steel with the seals molded to the apply piston.
I am assuming those are the good ones that cliff mentioned in his reply?

[Schurkey]

Originally Posted by 6D6GOAT

and i read on anther build that if you use a 34 element sprag then you have to REMOVE the 1-2 check ball??? should it stay or go?

Originally Posted by Schurkey

I have no idea why the 1-2 check ball would have any relation to the direct sprag.

Originally Posted by 6D6GOAT

Schurkey, yea that seemed odd but i just want to make sure. here is a link to that build. He mentioned that towards the bottom where you see the valve body separator plate pics.

http://www.crankshaftcoalition.com/w...0_rebuild_tech

What was actually said:

For a heavy duty application: 3rd gear shift use a .150" drill (#25 bit, .149) and leave the 1-2 check ball out. Caution: A 34 element sprag needs to be used with the 1-2 check ball removed.

Therefore you have it backwards. You do not need to remove the 1-2 check ball when using the 34-element sprag. You need to use the 34 element sprag when removing the 1-2 check ball.

The point being that with the 1-2 check ball removed, the shift will be so harsh that the 34-element sprag is needed to stand up to the shock.

I'm not saying I agree with that notion; but the 34-element sprag is just good practice.

[6D6GOAT]

lol i feel stupid. thanks for clearing that up. i didnt give that build a whole lot of time as i planned on doing jakeshoes mod.
thank you

[Half-Inch Stud]

Steel with permanent molded lip seal is a good (4l80) piston for reuse. clever design.

i'm old schoolin prefering the TH400 aluminum pistons, but have them molded steel pistons in one of my 4l80s.