Strengthening the 2004R - 2nd Attempt


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Strengthening the 2004R

(Let's try this one more time)

Strengthening a 2004R

Most failures in a 2004R are directly related to three things or three categories:

Due all you can to keep fluid as cool as possible. Higher stall converters produce more heat so they need more cooling.

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.

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.


OK, We'll start at the sump. With the acceleration and capabilities of a Turbo car or high horsepower car with weight, 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.

Ø Pans: Stock pan with 2004R filter, good driver.
Ø Deep Cast Aluminum with 700 filter, better and good for street/strip.
Ø 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 ¾" deep.
Ø Deep sheet metal aluminum pan, again new sump deep in the back of the pan is the
**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.**

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.

I have never seen a case break due to sheer power. It's always externally inflicted.

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.

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.

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.

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).

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.

Use stock OEM hardened shell. The Sun Gear and Planets are good to the low 9's.

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.

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.

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.

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.

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

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.

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.

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.

No changes needed.Just ck weld at front.
Stock clutches are fine

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.

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.

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.

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.

Man, I hate to type...


Buick Tweaker
man for someone who hates to type you sure do put out some good info.

poor printer...:(

you r da man da 2004r man...:D

hope your fingers heal soon my tranny's starting to make a clicking sound when stalling up but i'll get out of here and post it if i dont find my answer amounst your already printed knowledge