904 hard driwing when cold

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Old Nov 2, 2015 | 03:27 AM
  #1  
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904 hard driwing when cold

Hi


I have a 1970 challenger with 340 and 904.


When the car is cold the transmission have a hard time to make the car move, I need to give high throttle to make the car move.


When engine and transmission is hot, it works perfect.


Is it time for a new transmission ?


Regards


Tony
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Old Nov 2, 2015 | 10:36 AM
  #2  
TVLynn's Avatar
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during it's life someone transplanted a 340 into your car.... THE factory NEVER put a 904 behind a 340 motor. Your 904 probably has leaking seals.
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Old Nov 2, 2015 | 11:21 AM
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Might be something as simple as fluid and filter, I've had the filter plug up and not pull fluid when cold.
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Old Nov 3, 2015 | 02:02 AM
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Hi


Yes it is born with 318.






I will try the filter first Thanks.


What o rings are you meaning ?




Regards


Tony
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Old Nov 3, 2015 | 06:02 AM
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Tony -

Do a full tranny tune-up first.
New filter, fresh fluids - including what's in the torque converter, if possible. Making sure all the lines are open by flushing them, if possible.
When you drop the filter, you might want to drop the valve body as well and see how the stuff on top of it looks. Checking/adjusting the bands might be a good idea, since you're there.

Sorry, never worked on a 904, assuming the set up is similar to a 727.

Archer
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Old Nov 4, 2015 | 03:13 AM
  #6  
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Tks.



When I read about adjusting the rear band, I can see some places they want to turn back the screw 4 turns, and some other places only 2 turns ?


What is correct?


Tony

Last edited by Rute66; Nov 4, 2015 at 03:34 AM.
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Old Nov 4, 2015 | 08:03 PM
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Start the car.... Put it in neutral and for a couple minutes on warm up.... Then put it in drive.... That should help with the common "Morning Sickness"....
It is also referred to as Converter drain back.....


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Old Nov 5, 2015 | 01:19 AM
  #8  
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Hi




Is there a way to solve the problem?

(Converter drain back)




Regards


Tony
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Old Nov 5, 2015 | 05:26 PM
  #9  
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Originally Posted by Rute66
Hi




Is there a way to solve the problem?

(Converter drain back)




Regards


Tony
If draining , flushing and installing a new filter and fluid does not work?

One of my old 727's we took the valve body apart and use some 2000 or finer grit wet sandpaper on all the valving to remove any varnish buildup and possible burrs on the valves. Especially the torque converter control valve. This procedure cured this one.

On my current 727/904 race transmission, I found one of the hooked steel seal rings on the back of the pump badly worn. Once I replaced the hooked steel ring - problem solved.


$0.02

Last edited by Drag Pak; Nov 5, 2015 at 11:06 PM.
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Old Nov 5, 2015 | 05:38 PM
  #10  
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Yes.... Installing a new pump takes care of the problem... But at that point you might as well freshen up the trans complete....

Just My 2 cents....
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Old Nov 6, 2015 | 01:51 AM
  #11  
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Tks.


Regards


Tony
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Old Nov 13, 2015 | 08:55 AM
  #12  
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727 truck tailhousing instead of 904

Hi


I have a 727 SB with truck tail housing.




I can see the transmission is longer so I need another yoke and driveshaft.




I can also see it missing mounting holes for the shifter rod bracket, can I use the tailshaft from my old 904?


Do I need anything else?


Regards


Tony
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