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Aluminum drum bleed off ??

13K views 40 replies 17 participants last post by  fe3turbo 
#1 ·
I just picked an aluminum direct drum for my th400 and noticed a check ball in the drum behind the piston. Am right in assuming I dont have to drill a .060 bleed hole in this drum?
 
#2 ·
If your using a trans-brake valve body, you will need to use the trans-brake release springs and yes, the bleed hole will have to be drilled if the the drum doesn't have the trans-brake bleed hole . Also this is it usually how it works, a drum with check ball, no check ball in the piston, drum with no check ball, use a piston with check ball. Hope this helps. Burt
 
#4 ·
When the gear is releasing when the fluid pressure is released from that gear, it aids in disengagement. When you tear down serveral different years, we noticed that the check ball will either be in the drum without one in the piston, or not one in the drum but it will be in the piston.
 
#5 ·
Think you have this back words.....helps the apply piston,
keeps the piston from air locking while trying to apply
if it were the other way around you sure wouldn't need that there
.060 bleed hole, that bleed hole is recommended on all manual valvebody trans also, as it keeps the residual oil in the drum from appling the clutches in anything other than high gear.

hope this helps
 
#13 ·
The ball in the drum is designed to vent resignal oil when is the drum is spinning, other words, to prevent a centrifical application of the high clutches while it anti rotates in 1st gear, or while parts rotates in neutral.

Only one problem, it is designed to work at normal highway driving speeds and does everything wrong in a racing application.

Here is what happens in a race car.

Low gear - The ball not placed far enough out to vent properly, or doesn't vent at all with a trans brake application. Anti rotation applies and eventually burns up the high clutches while accelerating through low.

Second gear - No problems because the drum is locked to the case and parts are not rotating.

Third gear - Oil pressure seats the ball. But what most people are not aware of is at higher RPM,s centrifugal force unseats the ball causing a pressure leak just when and where you don't need it.

I laugh when I see after market aluminum drums with as many as three ball. What are they thinking?

Anybody have a fix for this? or better yet, anyone ready to get off of their trade secrets ?????
 
#15 ·
It will be hard to see on a logger Hutch, thats because at high RPM,s the pump delivers ample oil, I suppose the pressure reading is taken at the plug on the side of the case, so there is ample oil there to. The manual valve is a bottle neck, and most cast iron valvebodys have a horrible third gear circuit. The leak is downstream and wont show up on the logger.

Now think out of the box, Measure the surface that the ball seats on in square inches. multiply that by line pressure and this is the force that holds the ball on the seat, now spin that drum and that ball becomes awful heavy, too heavy to stay seated, if you could take a reading on the in the drum you would see the leak.

I didn't see this problem until I got involved with a car that ran in the low six second range, Two problems showed up, The high clutches were dragging in low gear so bad the driver could feel the drag by the seat of his pants in spite of his 3000 HP engine.

Cured that, but was still nipping the clutches on the shift, removed the ball, plugged the hole, and end of clutch problem.
 
#17 · (Edited)
Very good stuff really enjoy reading this! I also have heard that with higher RPMs some transmissions have been known to have clutch apply through Centrifuging residue fluid left behind the apply piston by residue fluid being thrown against the inside walls of the inner drum piston area thus pushing the piston partially applying the clutches? It would seem that the 1/16" hole drill in the drum and the heavier return springs should resolve any issues with this when a trans-brake valve body is installed. Burt
 
#19 ·
You got to remember when the trans brake is applied the high gear clutch is applied and the piston is full of oil and "under pressure", its not residue you have to deal with, its real oil. The ball is seated at this point and offers nothing as far as any help.

As the car launches, the high drum begins to anti-rotate. The heavier springs aid in exhausting some of the oil out through the trans brake valve, but the car is moving before the clutches have a chance to release clean.

As the drum spins up or anti-rotates through low gear, the remaining amount of oil is trapped in the drum by centrifugal force. The clutch tries to reapply but the 1/16 drilled hole gives the oil a path out.

I might add, the faster the car 60 foots, the worse the problem becomes.

I might also add, you guys who want to "neutral in the traps", the 1/16 hole does exactly what it is supposed to do, let the oil out of the drum. Allowing it to spin out of control and explode.
 
#18 ·
Most important note in the info griner posted is the "if it releases at all with a transbrake" the high drum goes from being clamped, to 6000 rpm in a split second, there is little time for the drum to exhaust, especially if just the ball and VB are doing the work...and outboard exhaust hole is always a critical item for fast/clean TB use - don;t care who's vb you use. That is just my advice.

As for the ball unseating at high rpm, I could follow that theory possibly. I would say it just make good sense to block the ball in pure racing application, not much to loose and might learn something, let you know.
 
#20 ·
What do you mean "don;t care who's vb you use". Compare a valve body to a cylinder head. only one flows air and the other flows oil.

You have only Nano-Seconds for the first and most important event to take place.

That Is, "Get the the oil out of the drum the proper way, through the valve body and out the trans brake valve. The better it flows, the better the trans brake works. This means a clean, simple and efficient oil path to and from the high drum".

If anyone running a 3 speed is burning high gear clutches, In most cases, look no farther than the valve body.

Just an opinion from me, the guy that invented the trans brake.
 
#22 ·
I.AM SURPRISED CHRIS CK-PERFORMANCE-WHERE ARE YOU .

I BELIEVE YOU HAVE ALREADY DONE A DIRECT CLUTCH-CHECK BALL TEST ON THE DYNO.
AND RECORDED A PRESSURE SPIKE OR LOSS READING AT AROUND 8,000 RPM I BELIEVE YOU CAN END THIS !!.

CHECK BALL SEATING QUESTION AND REPOST YOUR REPORT.
HAS THIS NOT BEEN ANSWERED MANY TIMES BEFORE ON YB ??.

AOK POP CORN READY WITH COFFEE AS WELL.
RAIN BLOODY RAIN.
AT LEAST WE DON'T GET SNOW HERE.

REG DAVID
 
#23 ·
I have always read where it is not a good idea to put the trans in neutral at the end of the 1/4 mile run because this puts the internals and planetaries into what they call Hyper rotation spin up thus spinning them faster then they were designed for thus causing a trans explosion by parts flying apart up through and out of the case. Warnings are also written here; http://www.tciauto.com/Products/ValveBody/ http://www.autotransdesign.com/motorsports_ServiceCenter/instrxHipsterTurbo400TransBrakes.asp
 
#26 ·
Well Im still kind of hanging here wondering if I should plug one of those checkballs or not. My current setup only has the checkball in the piston and I dont have any known problems with the direct clutches, but If its not gonna be worth the trouble to plug one of those checkballs then I dont want to waste my time.
 
#27 ·
I would not waste your time, I always use a piston with a check ball in the high gear drum.

I might agree with Griner in some very high H.P. applications, but I have yet to experience a problem like this even in my very high H.P. units.

Hope this helps
Dave
 
#29 ·
Hi

not trying to be rude or take the piss but did you really invent the trans brake. ? Im having a problem for three years and can't work out what to do? I've tested and tried many different things. just came to the realisation that my th400 has an aluminum drum with three check balls, a bleed hole drilled and a check ball in the piston.

problem is when inlet into top gear every single run at 7000 rpm its like the car goes into neutral and free revs. NO DAMAGE EVER AT ALL IN TRANS. PULLED DOWN THREE MEETINGS IN A ROW AND NEVER ONE ISSUE.

could this checkable thing be my problem. Domenic Adelaide Australia desperately needing some help
 
#31 ·
I have to call my old employer and ask how much he remembers..Maybe ask David... but somewhere around 78-79 a guy walked into the shop I was working at. His name was Dale Rose (If I recall correctly). Dale said he worked for GM and he designed the 400 valve body and much of the 400 while employed with GM. He sold my employer (on paper) designs for a internal 400 brake for $500. It was too long ago for me to remember the modifications to a stock valve body that we made but we spent months unsuccessfully trying to get it to work. Dale had claimed it was a draft and it needed fine tuning, but said the design was solid, and the only other person he sold the plans to was in Indiana, and drag raced a altered vehicle and they were having success with the design. Seemed like brakes were just coming out then... (I recall one that used a brake drum on the back... Not sure when Steve came out with a 400 brake... time line and location sure seemed close/coincidental to Dales claims....
 
#32 ·
Trickest early 400 I came across came from Ed Allesio @ Select. Observed it working in a low 9 second Camaro @ Moroso in 1982. Don't know if Eddie developed it or not, might have been from Vitar, just guessing about that. Bought a couple from Eddie Jr. about 10 years ago, Jr. sighed and agreed to make me a couple, customer had to have a internal unit that was OK for bottom bulb no delay application. This unit was pilot circuit, used the oem detent solenoid location, took me a while to figure it out, hat off to who ever did that one, totally trick by someone who got deep into the oil as we say. Truth be told, one of the units Jr. knocked out for me didn't work, didn't catch a shift kit hole some gomer drilled once upon a time, was a easy fix. Don't know if Jr. still is working in the shop or what, but that's one neat piece and Select was always a stand up shop in my experience.
 
#35 · (Edited)
If I remember right, S.G told me he made the transbrake transmission that was in John Lingenfelters Super Stock Corvette and Marv Ripes got a look at it that year at the NHRA California World Finals. Next year Ripes was a NHRA sponsor and had transbrake powerglides for sale. Ripes got the credit for the transbrake and NHRA made them legal. I saw the lock up converter trans at Griners shop that supposedly was in Lingenfelters Corvette that was outlawed by NHRA.

Steve was the nicest, down home, strangest guy I ever met. You could just feel the gears and trans fluid going around in his head 24 hours a day. He had a lot of ideas he never got too. He also got into circle track racing and built chassis in another shop in Mulbury, built engines, ran go carts, and loved Model T's. He won several hill climb competitions with one. Every one of those projects produced some unique parts and pieces. He also blew up a lot of Torqueflites with an old Funny car and NHRA made the trans shield mandatory. Correct me if my memory is off.

Steve and Dave Coan were also a great team at one time.
 
#39 ·
I've have direct clutches burning up for the last 2 years every 4 passes .Iv got a griner valve body with clean neutral. So hopefully this information I've read 4 times and pass it on to my transmission guys that have worked on my gearbox and can't fix the problem may now fix the problem. Thanks
 
#40 ·
Do you have a bleed hole drilled in the direct drum? . I just pulled apart my th400 , and the direct clutch pack was totally gone. Clutches had become steels, no clutch left on them. It had no bleed hole drilled in the drum or stronger springs, it had to have been applying in 1st gear at high rpm and killing the direct clutches, because my valve body and pressure was good, and the forward/intermediates were still like new.
 
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