TF 904 Upgrades

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drugster

drugster

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Hi:
Im in the process to rebuild my tf904 trans, trying to do it the rigth way but need a lot of advice because dont know a lot on transmissions stuff; so gonna put the engine and car specs and hope to get your help.
74 Plymouth Duster around 3350 pounds
414" small block with ported Edelbrock heads, mech flat tappet cam, 251/259@050, 580-601 lift, Airgap intake, Holley Ultra 850 carb, 11.5-1 compression.
4 linked 9" rear, 4.30 gears, 28" tall tires.
The car is used for weekends and 3 or 4 times a year to the track, shooting for low 11's or high 10's , already using a 3800 stall 9 1/2 converter.
My budget isnt too big but can do some savings to buy as much as possible.
Thanks in advance.
 
Youtube will be your best buddy.
(How to rebuild a 904 transmission)
(upgrades for a 904)
These kinds of searches will net you tons of info like this
Google <click here
 
My suggestion is to call either Andrews Racing, A&A Transmissions or Cope Racing Transmissions to get professional advice. You need something pretty serious for that much power. Not just your run-of-the-mill stock parts will do
 
I use stock disc and steels...I put 5 thin discs and steels in the front drum that usually holds 4,,,,I use the 24 spring kit for the front drum instead of the single wound spring...the thin disc used are the same ones used in the rear drum....probably best to use a 4.2 band lever...I use the solid rear billet servo that is available ..it is on ebay;;;
front and rear bands are kevlar....you can get a new pump gears if you want to...heavy duty band strut is available for the front band actuator......only thing that is pricey is the 24 disc spring kit around 100 bucks....you might not need it as it is used to keep the front clutch disc from drags at high rpm....what rpm I don't know....get a deep pan..and a big cooler...the sealing rings and rubber parts are just stock from Transtar or Transtec...You buy the high dollar kit you get the same sealing rings and rubber parts..

even with the 100 spring kit...you should be around 400 bucks to rebuild the 904..
 
70aarcuda said:
I use stock disc and steels...I put 5 thin discs and steels in the front drum that usually holds 4,,,,I use the 24 spring kit for the front drum instead of the single wound spring...the thin disc used are the same ones used in the rear drum....probably best to use a 4.2 band lever...I use the solid rear billet servo that is available ..it is on ebay;;;
front and rear bands are kevlar....you can get a new pump gears if you want to...heavy duty band strut is available for the front band actuator......only thing that is pricey is the 24 disc spring kit around 100 bucks....you might not need it as it is used to keep the front clutch disc from drags at high rpm....what rpm I don't know....get a deep pan..and a big cooler...the sealing rings and rubber parts are just stock from Transtar or Transtec...You buy the high dollar kit you get the same sealing rings and rubber parts..

even with the 100 spring kit...you should be around 400 bucks to rebuild the 904..
Click to expand...
Hey Tony when you put 5 thin discs in the front carrier do you ever get lucky and have enough clearance? When I did mine I tried the thinnest selective snap ring but still had to have the pressure plate milled down .035". I had 3 pressure plates and all were the same thickness. I think they were about .225" but it's been a couple yrs so I may be off a little. Thanks
 
I would got with a 998 trans. With a double wrap band. 5 clutches front, 4 in the rear.
Also i would go with 4 pinion planetarys!
 
fishy68 said:
Hey Tony when you put 5 thin discs in the front carrier do you ever get lucky and have enough clearance? When I did mine I tried the thinnest selective snap ring but still had to have the pressure plate milled down .035". I had 3 pressure plates and all were the same thickness. I think they were about .225" but it's been a couple yrs so I may be off a little. Thanks
Click to expand...

The 1st 3 that I did...I opened up the clearance...if I can remember ...I was getting some where around .050...and I had another .025 milled off the pressure plate to get into the .070 range...If I remember you need .010-.012 minimum clearance for each disc...
 
If you're curious about 904 tricks I know a few. I have a 511 BB bolted to my 904 with the JW Ultra Bell. 752hp and 658ftlbs in my 3077b Laser. Full season on it and its still shifting great.
 
Laser87 said:
If you're curious about 904 tricks I know a few. I have a 511 BB bolted to my 904 with the JW Ultra Bell. 752hp and 658ftlbs in my 3077b Laser. Full season on it and its still shifting great.
Click to expand...
Of course im curious! Will love to learn everything
 
drugster said:
Of course im curious! Will love to learn everything
Click to expand...

Where do i start... I started with a 77 non locker. After finding it had 3 pinion planetary from and rear I pulled the 2.74 low gear and 4 pinion planetaries from a 79 lock up. Drilled 1 1/4 holes in the sun shell to lighten it. Removed the governor and dead weight on the output shaft. New stock sprag and rear support. Drilled evenly spaced 7/16 lightning holes around the low/reverse drum and direct drum. Billet aluminum forward drum and hardened input shaft from A&A with tan frictions. 5 tan frictions in the direct drum after machining the pressure plate down and playing with snap rings. Also used the reverse wound spring from ATI. Split low/reverse band and kevlar direct band. 5.0 lever. Spot weld a reinforced plate t the band strut. Tossed out 1-2 accumulator spring. Removed rear servo spring and locked with shims (washers). Deep aluminum pan with reusable gasket and reusable big brass filter.
 
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70aarcuda said:
Billet aluminum drum?
Click to expand...

"Forward clutch retainer" I spun the shaft clean out of the cast drum

IMG_1569.JPG
 
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Reviving an old thread as this is about the only one ive found talking about the ati reverse wound spring. Wondering if anybody else has used it and what your thoughts on it were?
 
I have one in a 904 but the car is not done, probably will not hit the track until next year. The car moves under its own power, so I know the trans is working.
 
drugster said:
Hi:
Im in the process to rebuild my tf904 trans, trying to do it the rigth way but need a lot of advice because dont know a lot on transmissions stuff; so gonna put the engine and car specs and hope to get your help.
74 Plymouth Duster around 3350 pounds
414" small block with ported Edelbrock heads, mech flat tappet cam, 251/259@050, 580-601 lift, Airgap intake, Holley Ultra 850 carb, 11.5-1 compression.
4 linked 9" rear, 4.30 gears, 28" tall tires.
The car is used for weekends and 3 or 4 times a year to the track, shooting for low 11's or high 10's , already using a 3800 stall 9 1/2 converter.
My budget isnt too big but can do some savings to buy as much as possible.
Thanks in advance.
Click to expand...
Lots of pics of my 904 in my profile.
 
It's my understanding that the stock third gear clutch return spring will expand in the middle at over 6,000 rpm; causing the third gear clutch to drag in first and second.
 
Laser87 said:
Where do i start... I started with a 77 non locker. After finding it had 3 pinion planetary from and rear I pulled the 2.74 low gear and 4 pinion planetaries from a 79 lock up. Drilled 1 1/4 holes in the sun shell to lighten it. Removed the governor and dead weight on the output shaft. New stock sprag and rear support. Drilled evenly spaced 7/16 lightning holes around the low/reverse drum and direct drum. Billet aluminum forward drum and hardened input shaft from A&A with tan frictions. 5 tan frictions in the direct drum after machining the pressure plate down and playing with snap rings. Also used the reverse wound spring from ATI. Split low/reverse band and kevlar direct band. 5.0 lever. Spot weld a reinforced plate t the band strut. Tossed out 1-2 accumulator spring. Removed rear servo spring and locked with shims (washers). Deep aluminum pan with reusable gasket and reusable big brass filter.
Click to expand...
Were you running the stock input shaft when you broke that drum.
I cannot believe you broke that drum before you broke the stock input shaft. What valve body are you using in your trans.
Any sprag trouble at your power level?
 
drugster said:
Hi:
Im in the process to rebuild my tf904 trans, trying to do it the rigth way but need a lot of advice because dont know a lot on transmissions stuff; so gonna put the engine and car specs and hope to get your help.
74 Plymouth Duster around 3350 pounds
414" small block with ported Edelbrock heads, mech flat tappet cam, 251/259@050, 580-601 lift, Airgap intake, Holley Ultra 850 carb, 11.5-1 compression.
4 linked 9" rear, 4.30 gears, 28" tall tires.
The car is used for weekends and 3 or 4 times a year to the track, shooting for low 11's or high 10's , already using a 3800 stall 9 1/2 converter.
My budget isnt too big but can do some savings to buy as much as possible.
Thanks in advance.
Click to expand...
What year is the trans you have now.
 
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