A904 Pump Gears

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Nick Mailloux

Nick Mailloux

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Im in the process of ordering all my parts for my 904 rebuild. Im trying to figure out if all 904 pump gears are the same. Some sites list the gear as fits all 904s and some specify lockup vs non lockup with two different measurements. What gears do I need for a 70 a904?
 
1970 would be non-lock-up.
Lock up transmissions didn't start till around 1978. I'm not familiar with any other differences related to the pump gears.
Valve bodies don't interchange either.
 
I know it's no lockup, that's not what I was asking, I'm asking what's the difference between the gears? I can't really find any for sale that as marked below 78. I appreciate it though.
 
Nick Mailloux said:
I know it's no lockup, that's not what I was asking, I'm asking what's the difference between the gears? I can't really find any for sale that as marked below 78. I appreciate it though.
Click to expand...
This should help.
904 pump gears. lug style. 1960-2003 : The type you have.
904 pump gears. Milled flat style. 1993-2003
My catalog shows no size differences listed for either type(one size fits all in both cases?), just they two types, lug or milled flat.
It makes no difference if the transmission is a lockup or non lockup.
The rear clutch spring is listed for 904's from 1960-2003, but I don't know that they were in all 904's, although we did sell a fair number of them.
 
Last edited:
transman said:
This should help.
904 pump gears. lug style. 1960-2003 : The type you have.
904 pump gears. Milled flat style. 1993-2003
My catalog shows no size differences listed for either type(one size fits all in both cases?), just they two types, lug or milled flat.
It makes no difference if the transmission is a lockup or non lockup.
The rear clutch spring is listed for 904's from 1960-2003, but I don't know that they were in all 904's, although we did sell a fair number of them.
Click to expand...
This is exactly what I needed! The measurements I was talking about was the the thickness. It says the 60-77 is .7460-.7470 and 78-up is .7476-.7489 so only a thousandth or so thicker. So I ordered the two lug style part number 12530A, which is listed as 78-up as that's all that available anyways. Only a thousandth difference, worst case it will just tighten my pump clearance by .001.

Screenshot_20190602-102545.png
 
Looks pretty nice. Did the converter crack down at the bottom of the slot? Put oil on it, tap it a few times, wipe it off, then tap it again for the oil to come back out of the crack.
 
CudaFactHackJob said:
Looks pretty nice. Did the converter crack down at the bottom of the slot? Put oil on it, tap it a few times, wipe it off, then tap it again for the oil to come back out of the crack.
Click to expand...
No idea, stock garbage converter was tossed in the scrap pilw , picked up the trans used for $50. I'm rebuilding it it some beefier parts for my dart.
 
I note your pump bushing was not staked either; someone that was not familiar with it reworked it and installed the converter incorrectly and tightened the trans to the engine and then snapped the pump tab maybe??
 
transman said:
This should help.
904 pump gears. lug style. 1960-2003 : The type you have.
904 pump gears. Milled flat style. 1993-2003
My catalog shows no size differences listed for either type(one size fits all in both cases?), just they two types, lug or milled flat.
It makes no difference if the transmission is a lockup or non lockup.
The rear clutch spring is listed for 904's from 1960-2003, but I don't know that they were in all 904's, although we did sell a fair number of them.
Click to expand...
Hoping you can help me. I just rebuilt my 904 that was in my 65 Dodge Dart twice( after the first time I got a little over excited at having it on the road for the first time in 3 years and smoked the clutches). So we put in new clutches and re installed it. Now I have no gears whatsoever. Think it's the pump so I'm looking to buy a new/reman one or a rebuild kit for the pump. Any ideas on where I can get one? I've looked online and can't find anything. Thanks
 
Jesters65 said:
Hoping you can help me. I just rebuilt my 904 that was in my 65 Dodge Dart twice( after the first time I got a little over excited at having it on the road for the first time in 3 years and smoked the clutches). So we put in new clutches and re installed it. Now I have no gears whatsoever. Think it's the pump so I'm looking to buy a new/reman one or a rebuild kit for the pump. Any ideas on where I can get one? I've looked online and can't find anything. Thanks
Click to expand...
First, have you put on a pressure gauge and verified there is low or no pressure being produced when its running? Thats the first thing I would check. Then I would verify converter engagement to the gears, and or damage from not getting the converter in all the way.
The pump only has 4 parts technically, the stator, the pump body and the gears. Inspect the housing and stator for any wear, pumps and gears can look discolored, but if there isn't anything you can catch a nail on or physically feel you're probably ok. There is a spec for clearance between the gears and housing and stator plate. If you do need gears or pump parts I would call A&A Transmissions, they are amazing and have supplied me with countless 904 parts (317) 831-3066. They have new oem gears, reconditioned and aftermarket gears, housings etc.
Also personally from experiance, these pumps normally just don't up and quit, they get weaker from wear, worn enough to push fluid out of the vent but still work, there's probably a different issue.
 
If the fluid level is above the full mark in neutral and it won't move; pull it out and take it apart....THEN order parts.
 
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