How about a good Drag race 904 build discussion

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Dang, I could have built at least 12-904's since this thread started and I got a full time job as well! Lol

Like cracked says.... Pick your parts and pay your $$!

Tony - 70aarcuda has most whipped on the usage of his 904's. The recipe is an xlnt choice of parts and they work very well together!

Mine is mostly a street car. Motor is maybe 525HP or so and I smack it with a 200 Hit of NOS. I also have a TB with low band apply. I drive my car all over the place and beat on it like a red headed step child! Take that for what it is worth.
 
I think this thread should be moved to the transmission section of the forum.
 
I had a turbo action 8 in converter that cracked the hub...send it to Continental Converters in Southern Cal back in 93......they welded on a new chromemoly hub and that converter probably has several thousand runs on it since.....only one I ever had crack..but it is from the early 80s....
 
Transact of Indy will do them either way you want. With or without Low Band Apply on any of their Valve Bodies, with or without a brake.
 
i have one of their lba reverse manual valve bodies, without transbrake. For the price i dont think they can be beat. I hope to get out testing it by the end of the month.
 
You guys are saying your trans brake does not apply the band when you are staged with the brake on right. You don,t mean it does not apply the band when you are in first gear without the brake on when using it as a manual shift body. Correct?
Does this company make any claims that the model without the band off has a better 1-2 shift.

As I understand it, this is the challenge that the different manufactures face when trying to use band on. They want to protect the roller clutch, but also avoid band overlap on the 1-2 shift.
I talked with Turbo Action jus a couple weeks ago and they told me that they routinely evaluate their competitors brakes and have updated theirs 4 times since it initial release.
They tell they they leave the band on for a longer period of time than most of their competitors do because they believe their is to much chance of roller clutch breakage if the tires would break loose and then grab again.
Yet their manual shift version has no band apply. But they maintain a no band apply has a superior 1-2 shift regardless of brand.
Yet Griner claims to now have the best of both worlds.
Also Tony( hope it's ok if I call that) regarding the chrome moly converter hub.
I had Turbo Action build me a 4600 8 inch pro series converter about 8 years ago.
At that time they offered the chrome moly version with a thicker wall that required a machining off of the ring on the reaction shaft so the converter would go on. Do you recall if you had to perform this modification to yours when you had your converter repaired.

Duane
 
Hey buddy . Was not tryin to start a feud with you. Came here to make friends and share experiences. Racing is not cheap and I understand your skeptism when someone comes out with a new component. I also am not suggesting that everyone should run out and buy one or an aluminum drum. As you said . Those were my personal choices.
I also understand that there are some disagreements about drum explosions only happen to 727,s . I read something on another thread where a guy said the 904 drum can spin to 24,000 rpm without letting go. That may be true. The few that I have seen I never investigated to see which model trans it was.
But If I may I would like to offer my justification for my purchases.
Every company that offers a low band apply is trying to protect the roller clutch from damage by what I will call reverse engineering No torqueflite was ever designed to leave a starting line at some extreme rpm. So they have tried to design the valve body to do what racers demand of it and not hurt the clutch. As I understand it the challenge is to still keep a clean 1-2 shift.

When Turbo Action sells you a converter or manual shift valve body, they also supply explicit instructions not to do a burnout in 1st gear, because they are trying to protect the roller clutch.
When I read Carl Munroes torqueflite book in the opening paragraph .written by Carl and Rick Allison they emphasize the need to do everything possible to protect the roller clutch. They also mention if I am reading it correctly, two possible methods of failure on the 727. One pertains to the cam failing, the other to the rollers.
All these years using the 904 there has been no other alternative but to use the stock roller clutch. But finally all these years later Ati in conjunction with Chrysler have decided to make a better mousetrap. In my book that is not a sales pitch, but a wholesale improvement.
By racing standards $ 350 is cheap insurance when using a valve body with no band apply like I have. You only have to take a very close look at the pictures of that new clutch to see the patented ingenious of it.
As for the drum in a 904 it may not explode , but you can still break the roller clutch
The best improvement in 1-2 shifts in my car never came from a valve body, it came from a light drum and sunshell that make it way easier for the band to stop it spinning when called for.
The cost for the drum versus performance gained is probably comparable to the similar money spent on the engine. There is no such thing as a ten second car. There are just different way to make your car run tens. If I am late on the tree, and cannot run my dial in, then yah they are all gonna go by me.
I too am on a budget. Have not put money into the car in years. Cost me $100.00 dollars to rollerized my trans myself cause I am a Toolmaker by trade and have access to machinery for free. I too would never pay for one of those high dollar trans.
Hope we can agree to disagree and be friends. I know I am new around here but I have built my fair share of torqueflites for a lotta years too. But hey I am always willing to learn something new.
That's why I ,m here.
No hard feelings I hope


Duane
 
You show me ONE 904 that has had a front drum explosion behind an engine like you have. You won't find one. I've been at this for 40+ years and I've never seen or heard of a 904 explosion, EVER. Seen plenty of 727 carnage. The engine needs to turn around 10K rpm where the 904 front drum reaches critical mass. Good luck getting there!

All those "fixes" are a waste of money in a 904. I've stupidly run a 904 for over a year after a rear gear explosion without ever having the front drum exit the case. The same situation that tends to roll sprags.

You plan on driving that thing on the street with an aluminum drum... have fun changing fluid all the time to keep the aluminum grit out of everything. Ever seen a pan of a car with one after 1K street miles? Loaded with crap.

It's a good idea to know what to do when running a TF to protect the trans from damage. I never tend to use a LBA valve body, however, I learned and listened to those that were smarter than me to do what was right when a TF was in a car. Those same guys told me about the waste of money the fancy drums/sprags are for a 904. There are MUCH better places to spend that 900-1000 to gain hp at the tires.

Do you need full body armor if a kid shoots a spit wad at you? That stuff is overkill and totally unnecessary. Same with the better mousetrap parts. They provide no additional safety to you or your car.

I have no dog in the fight when it comes to your wallet, however, I also have not tried to talk you into any "upgraded" parts, when the factory pieces are wholly sufficient... think about that. 1# out of the rotating assembly = 7hp to the rear tires, sure it does. A 904 takes about 25hp to run, so if you use a front drum that is 3.5# lighter it adds HP or takes no hp to run? Ummmm NO. Don't believe everything in a catalog or what a salesperson tells you.

I have no ill will towards you. Hate to see people waste money in a hobby that is inherently expensive. Why punish your wallet.

Pick your parts, pay your money!
 
Are you saying that after your rear gear breakage that you should have checked the roller clutch?
I do not drive my car on the street.
I run external filters in my cooler lines to minimize the aluminum debris. But yes you need to change the fluid once in a while.
I never said the new roller clutch would make my car faster. But I am hoping it will be more reliable and durable.
I do not believe everything I read in a catalog. I believe my Et slip.
As I said in a previous post my car dropped its et over half a second in performance with no change to the motor. Ymmv as they say.
I have already agreed with you that I have not seen a 904 explode a front drum.
But there seems to be confusion as to the root cause of a 727 only drum explosion.
As I understand it the drum in a 727 over speeds only if the roller clutch does not lock like it is supposed to. It is a by product of the failed roller clutch. Now how is that clutch installed in a stock 727. It is splined into the aluminum case.
As I understand it, sometimes those splines strip right out of the case. If it does that the clutch cam will spin right in the bore. The fix is a bolt in cam. If the splines do hold the other type of failure is for the inner race to over power the roller and break. The fix for this is to add more rollers and reduce the amount of load on each one. Or the other fix is low band apply so the clutch sees none of the load at all.
The stock 904 cannot spin in its bore because it is riveted to the case. This is equal to a bolt in clutch cam. So it cannot fail that way. But even the 904 can still over power the rollers..
The difference is the 904 just loses first gear.
Do you disagree with this explanation.? If you do not can you explain to me in technical terms why you disagree.
You acknowledge that the 904 only uses 25 horsepower. Can you give an explanation why it uses less horsepower.

Thanks

Duane
 
The rollers in my 904 fell out... the drum never exploded and the car drove fine for a while.

You are applying a known issue for a 727 which can be devastating, to a 904. They do not have the same risks.

Your explanation and some of the fixes are close enough regarding failure and consequences related to a 727 only.

904 is smaller and more efficient.
 
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