Strengthening Tranmission
by Bruce (WE4)
Strengthening a
2004R
Most failures in a 2004R are directly related to three things or three
categories:
1) HOT TEMPERATURE KILLS:
Due all you can to keep fluid as cool as possible. Higher stall converters
produce more heat so they need more cooling.
2) PRESSURE AND HYDRAULIC CONTROL:
Keep well serviced and valve body modifications (i.e., shift kit) should be
installed in any 2004R. The level of control (pressures and line) depends on
engine output and driveabiliy options.
3) MECHANICAL LOAD AND FATIGUE:
OK, Someone is always gonna say "well, that's not how my buddies
broke" or " I've never seen one break". So we'll talk in
"Tendencies". As we work on and test more 2004R's and get more tech
calls or e-mails for 2004R's than most, I can tell you for sure what
"tends" to fail and as to, why. I don't want this to be an
advertisement but I do want you all to know how, why and who addresses these
issues.
TECH
OK, We'll start at the sump. With the acceleration and capabilities of a Turbo
car, they have a tendency to cavitate. Why? The factory did a poor job of pan
and filter design. It is uncovered with fluid, easily. Reason we have seen this
is poor scavenge.
In other words the pump is sucking and pumping, the converter uses a large
amount of fluid, as it is a fluid coupling. Large coolers are used so under hard
demand getting the fluid back to the pan is, let's say slow or delayed in
returning to pan. Now add in the acceleration "G" force factor and the
"little" or "restricted" return becomes important cause the
fluid you do have has rolled up the back of the pan uncovering the 1"x
2" hole in the filter. The 700R4 design is better but same problem
prevails. 700's have more fluid in the pan over the sump than 2004R's do, and
pick up from bottom, so it is less likely to cavitate but it can still occur in
700's also.
OPTIONS:
� Pans: Stock pan with 2004R filter, good driver.
� Deep Cast Aluminum with 700 filter, better and good for street/strip.
� Shallow sheet metal aluminum pan, fluid is always cool and with the new rear
pickup T/F filter design is excellent for street/strip and is only 2 �"
deep.
� Deep sheet metal aluminum pan, again new sump deep in the back of the pan is
the
best.
**All tests were done with very sensitive pressure gauges to insure results, the
more we moved the sump to the back and bottom, the more consistant and rock
solid pressures were found.**
NEXT THE VALVE BODY:
Valve body modifications are modifying or controlling where and how fluid is
directed to do what job and when. Shift timing is critical to this transmission,
and the more power put to it, the more critical it becomes. This is known as a
" shift kit". However, "shift kit" is a trademark of Gil
Younger at Transco. Everybody has a kit--Superior, Art Carr, Level 10, Transco,
B&M, TCI etc... In my opinion and best for the buck was the
"Original" Art Carr's High Tech Kit. Simple yet not destroying and
worked very well. Sometimes the T/V spring in the kit was a little stiff for the
application but in those cases use the stock BRF. As far as drilling the plate,
bigger is better is NOT the way to get the results you desire.
CASE:
I have never seen a case break due to sheer power. It's always externally
inflicted.
OUTPUT SHAFT:
I have only seen three twist: Eric Schurtz"s Stage 2 car, 9.59secs. Brian
Burnside's Stage 2 car, 9.99 secs, and a truck we converted from a 400 pulling a
30,000 LBS load. So I would say at stock weight (3700 lbs) you are good to 990
or so. Whats been done to improve the output shaft? I called my shaft
consultants and they analyzed the shaft. They said that by "process"
they could maybe gain 20-25% but after that a new billet piece would need to be
made. Nothing further has been done.
PARK GEAR:
Nothing needed. It's strong and good to whatever. We install a Torrington low
drag bearing. But it serves more purpose on lessening parasitic drag and coast
than on drive, because under acceleration the planet is trying to drive away
from the gear, not into it.
LOW/REVERSE CLUTCHES:
Unless you run a trans brake any good paper lined, name brand clutch will work.
With a trans brake I would recommend the Raybestos High Static. They are
designed to hold better statically meaning no shift: holding clutch.
LOW PLANET:
No problems but new roller clutch is suggested. This is the part that takes the
load using the Stage Right or similar style brake (Not the Bat Brake).
LOW REVERSE CENTER SUPPORT:
This washer Center Support to Sun Shell is the most common to fail. PTS installs
a roller bearing in the face for more dependability. These are asked for more
than any other part we make. Running from stock to the nines it's the way to go.
SUN GEAR AND SHELL:
Use stock OEM hardened shell. The Sun Gear and Planets are good to the low 9's.
FORWARD DRUM:
Here is where you get the most debate. Some have broken in the 14 second cars
others live in the nines. All I can say is the people of India (where the metals
came from for GM) must be some very inconsistent people. 1800 series hi carbon
steel is what they were made of. Very close tensile and yield strengths (BAD).
Fatigue also plays a factor. Someday hold one up and look at the spline area.
All the power runs through that piece. See, detonation and traction are what
load and unload. When it fails it is very fast and very violent. Now processes
have been tried, hardening, annealing, softening, tigging and cryogentics. All
to which have been to no avail. We came up with a billet shaft and a way to fuse
it to the drum and reinforcing the drum during this process. During testing no
other "process" passed the 500 ft LB rating. The billet ones went to
1350 ft lbs, and Boeing and a subcontractor to them did these tests. So numbers
can be presented. We also replace the plastic thrust washer with a bearing. Oil
and Lube to direct clutches is improved also.
I recommend use 12.0 and under with heavy foot.
DIRECT DRUM:
The direct drum must be within .030 of original diameter. Cannot be bent or heat
deformed. All steels must slide freely in bore. In ring bore, no ring cavities
can be present. One of the most common 2-3 flair symptom is , bore is ring
grooved near bottom of drum using cast iron rings. Band surface must be
perfectly flat, no scores, especially with the use of the new band. Teflon rings
are recommended.
Direct drum good to whenever mid 9's.
BANDS AND RELATED:
We have tried and tested all kinds of bands. The Raybestos Pro Series had the
best lining but when pressures started going up, anchors started coming off. The
Banco Reline worked very well with a stock design base and red lining. Nothing
special done to anchor but only broke one. Borg 210's gave me the best luck but
every 15-20 or so one would fail. Anchor most of the time. Then Alto came up
with an extra wide band done very nicely and anchor problem is solved. We beat
this thing up and not one failure.
Alto, I think hit a home run with this band!!!
Recommended 14.0 and under.
BAND ANCHOR PIN:
Again many have broken and many have not. Available now are 300M material pins
that are .002 larger in the case bore (to take up the slack from stock pin
walking) and .004 larger on nipple that actually fits in band. They are longer
so they can be each custom fit to your case. (Cases are not all perfect and do
wear.) Unbreakable.
For the dollar install every time at any power level.
SERVOS:
A modified GN servo works well up to high to mid 11 sec cars, then the billet
one should be used. The pin is modified according to the drivers likeness
CENTER SUPPORT:
Another common 2-3 flair is crossleak in center supports. Ring land wear. First
of all teflon ring everything and hand fit. Teflon bushing is used in direct
drum. All ports are checked for crossleaks. All should do this. For street/strip
cars the killer street unit has a large bearing on the center support between
drum and center support. The center support is crossed drilled for lube and then
polished. A bearing is cut into the front for contact with OD ring gear. Again
less parasitic drag. No real strength gain, less drag less friction.
OVERDRIVE RING
GEAR:
The OD ring gear is strong enough to withstand low 11, high 10 sec passes. Some
of the high horsepower or heavy cars are now breaking these. Also the planet and
stock input shafts are now being seen failing. The billet drum shaft is strong
as ever and the next weakest links are beginning to surface. This question was
asked about 2 years ago and now we have some answers.
3+4 CLUTCH
4th clutch, a 3 clutch piston should be used (2 is stock). A stock cut to .070
will work just fine.
4th gear clutches of any brand will work.
OR CLUTCH
No changes needed.Just ck weld at front.
Stock clutches are fine
OVERDRIVE PLANET:
The OD planet is notorious for cracking the splined pieces and or stripping the
splines. This can happen from a 15 sec Olds to a high 9 sec car. This piece is
going to need to be addressed to continue to put hard power to these
transmissions. I was really hoping someone else would step up and make the OD
planet and ring gear, but everyone seems to think that it's a losing effort. It
will be the next part addressed by us but I need to gather my bearings before we
take on any more. I have two ideas in the works, but right now they are just
that, thoughts and ideas, but I do have people on it. Wish another company would
get involved.
INPUT SHAFT:
The input shaft has a tendency to break in two ways. First is at the planet.
Second is at the splines in the converter. There are two designs of input shafts
stock. First is the "blind spline" type. With these, the planet
splines kinda spline into the bearing journal . The other has a distinct
"grove" between splines and journal. The "blind spline" one
is stronger but their limit is about 600 ft lbs of torque. Now that's total and
or spiking or shocking 600 ft lbs which most high to mid 11 sec Buicks are
capable of. With a T-brk use and real low 11 sec or heavy cars, these are a must
for reliability.
PUMP:
All should have hardened stators and chrome moly rings. We recommend a 10 vein,
as they are reliable. Use GM parts only! Boost valves are cheap insurance. A
.500 T/V boost valve is recommended and the 1-2 boost valve can be either .300
or now .400 ones are available. Pump modifications were published in a thread
recently. Search for it. Pump body should be teflon bushed and seal loc-tited
in.
GOVERNOR:
The governor spring should be pinned in. We recommend the setscrew method.
Well, this is just one opinion. There will be builders and owners that have had
better luck and guys that have had worse luck. There will be people who say,
"I have never seen that" or "I did it before that point."
Like I said in the beginning I said "tendencies". The original quality
and consistency of the parts used is broad. This is not law but a recommendation
or guideline. However I do feel that if you can reduce the likeliness of a
problem and maybe overbuild to avoid having troubles down the road, why not?
Money? How much to repair a transmission when it fails? Just an opinion. So if
you want to lock the converter and or put some reliable power through a 2004R,
this is pretty close as to what you have to do to make it live.
Bruce (WE4)
http://WWW.PTSNCTB.COM