904 Parts

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Bad Sport

Bad Sport

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OK, it's time to start collecting parts to rebuild a 904. Any suggestions as to what parts to purchase, kits etc?

My plans for it are hot street/mild strip occasionally, nothing really radical at this point. It will have a custom converter built for it once I have my engine specs set in stone.

I already have a valve body upgraded with the TF-2, other than that I'm clueless.

LOL, this will be my first attempt to rebuild one. :toothy10:
 
I just rebuilt my first 904, it's pretty straight forward. Get an ATSG manual, go to YouTube and watch the 19 part series for 727 rebuild, the 727 is almost identical having larger parts. In YouTube type in "rebuilding 727 torqueflite 600hp". There are also some other little short videos found when you type in 904 torqueflite. Having a shop press will be handy for rebuilding front clutch pack and replacing bushings. And air compressor for testing clutch packs and servos.
Use search function here, a lot of the questions you will have are here as well.
For parts many of the American guys have some favourite places to buy, in Canada I used TCS for parts(which also does a lot of American sales). I bought my servo/accumulator upgrades through Makco.
My 340 going in front of my 904 is probably gonna make about 400hp, I'm guessing you'll be in the same range. I went with 24 return springs module for front drum, and the other basic upgrades like high friction clutches, kolene steels and HD bands. I left mine as is with 4 clutches each front/rear. I replaced bushing and put a new gear in pump. Replaced springs and rollers in the one way sprague. My valve body is a full manual, I prefer to shift my autos manually then mess around with kickdown linkages, plus I like shifting. This 904 is forward pattern and my Demon's 727 is reverse, I wonder how often ill mess that up, doh.
Just watch videos and read manuals and other threads here. I also have the HPBooks Torqueflite A-727 Transmission Handbook, which has been handy too.
Good luck with the rebuild.
 
I get most of my rebuild parts from www.bulkpart.com and shop around for the best deal on any high perf parts I need at Cope Racing, A&A, etc. Something else you might need are specific select snap rings to get the clutch plate clearances set and you can find them at www.wittrans.com There are numerous good converter builders. I'm running a PTC and it works great and didn't break the bank.

There really is no specific manual for a 904 except the factory serv manual or the ATSG manual which is nothing more than a copy of the factory serv. manual but Karl Munroe has a good manual out for the 727 which is very similar and it contains a lot of information on theory and operation and high perf. mods. Here's a link to it on Amazon

[ame="http://www.amazon.com/Torqueflite-A-727-Transmission-Handbook-HP1399/dp/B00E84G4BI/ref=sr_1_fkmr2_3?ie=UTF8&qid=1396231141&sr=8-3-fkmr2&keywords=karl+munroe+727"]Torqueflite A-727 Transmission Handbook HP1399: How to Rebuild or Modify Chrysler's A-727 Torqueflite for All Applications [Paperback] [2003] (Author) Carl Munroe: Amazon.com: Books[/ame]

The YouTube video's Rodzilla recommended are a great way to actually see things done. Gives you an idea on tools needed also.
 
All good info Tracy, but exactly what parts would I want to get to toughen the 904 up and what parts can be reused?.

As far as the converter, I already planned to talk to PTC.

I need to make a list so I know what I need and how to budget for it.
 
Are you planning on a 5 clutch forward drum, or the factory 4?
(A new pump and drum for that)
Bolt in 16 roller rear sprag?
Solid front band instead of flex?
Billet front band and low/reverse servos?
steel planetary set for low/reverse?
4.0 band apply lever?

These are some of the choices, but I'm not as up on it as Tracy is so he could probably tell you more about which things would be a good idea for your HP range.
I was an Aamco shop foreman/builder, but I did mostly sticks and exotic automatics. (BMW, Mercedes, Volvo, Panterra, and Allison)
Had my share of TF's, C4&C6 Ford, TH200-700R4 and transfer cases, but it been a long time back now. :)

If you need assy help or have questions I can still remember the basics. :)

"Fluid goes on the inside Greg" :)
 
It depends on what the HP and TQ level of the engine is. For anything under 400 hp you really only need a good rebuild kit that includes quality (Raybestos or equivalent) friction plates, new steel plates, a new front band (rear band is ok to re-use if it's in good condition), all new thrust washers and bushings, new pump gears or pump assy, sealing ring and paper kit, a multi spring conversion kit to replace the single wound spring in the front clutch, a 4.2 ratio front band lever, a billet rear servo piston, new rollers and springs for the sprague.

Above 400 HP I like to upgrade to either red lining or blue plate clutch frictions and front band. You might need some selective snap rings to properly set the clutch plate clearance. You also need to set the total end play so you might need a selection of different thickness end play thrust washers.
 
Unless you are turning it some higher RPM, the wound spring works OK, you can save the 100-120 on that kit. It's RPM that unwinds the spring, not necessarily HP.

You should be able to build a good street strip trans in the 250-300 range depending on how involved you want to get.

I never bother with an upgraded sprag. They aren't really an issue in 904's like in 727's.
 
crackedback said:
Unless you are turning it some higher RPM, the wound spring works OK, you can save the 100-120 on that kit. It's RPM that unwinds the spring, not necessarily HP.

You should be able to build a good street strip trans in the 250-300 range depending on how involved you want to get.

I never bother with an upgraded sprag. They aren't really an issue in 904's like in 727's.
Click to expand...

727 stock sprag is pressed in and held with a set screw...if it spins..it ruins the case...the 904 is held by rivets..a bolt in sprag just replaces the rivets...nothing is gained...if the stock 904 sprag retainer is damaged then the rivets can be drilled out and replaced with a bolt in one..
 
Thanks Gentlemen, this is pointing me in the right direction.

As far as HP, probably in the 400HP range, and I will twist it to 6500 occasionally.
 
TrailBeast said:
Are you planning on a 5 clutch forward drum, or the factory 4?
(A new pump and drum for that)
Bolt in 16 roller rear sprag?
Solid front band instead of flex?
Billet front band and low/reverse servos?
steel planetary set for low/reverse?
4.0 band apply lever?

These are things that I need recommendations on, since I have no basic idea of what I need to build a durable 904.

I could grab the basics through research, but I would prefer to go beyond the basics enough to give me confidence that it won't fall out of the car under some frisky driving.


"Fluid goes on the inside Greg" :)

LMAO
Click to expand...


..
 
crackedback said:
Unless you are turning it some higher RPM, the wound spring works OK, you can save the 100-120 on that kit. It's RPM that unwinds the spring, not necessarily HP
Click to expand...

Hey Rob, I'm not a 904 guru as you know. I have read that anything above 5500 is pushing it with the stock spring but what do you think?
 
6Kish. A weak one might unwind earlier.

What engine is getting spun to 6500, the xe268H cammed 318? A 320-375hp build doesn't require anything fancy.

Pick what you want to throw in it and go.
 
crackedback said:
6Kish. A weak one might unwind earlier.

What engine is getting spun to 6500, the xe268H cammed 318? A 320-375hp build doesn't require anything fancy.

Pick what you want to throw in it and go.
Click to expand...

No, I'm putting together a 360, high stall converter with steeper gears (possible 4:56's).

BUT, the teen has seen 6500 on occasion. :D
 
The spring kit cost 100 bucks....if you got the budget for it...replace single wound spring and sleep good at night
 
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