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ID this trans, 904 or some derivative?
https://slantsix.org/forum/viewtopic.php?f=20&t=63551
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Author:  drgonzo [ Thu Apr 25, 2019 9:01 am ]
Post subject:  ID this trans, 904 or some derivative?

Supposed to have been pulled from an '81 pick up. Does it being a truck transmission make it a difficult swap into an A body? Do I need to keep looking for an A body 904?
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Author:  Dart270 [ Thu Apr 25, 2019 10:50 am ]
Post subject:  Re: ID this trans, 904 or some derivative?

Yes, looks like a Slant 6 904. Should be a direct swap to any A-body. Assume you know about large/small crank hub/pilot hole and converter match up...

Lou

Author:  drgonzo [ Thu Apr 25, 2019 10:53 am ]
Post subject:  Re: ID this trans, 904 or some derivative?

Yes I am aware of the input shaft sizes and such. That is one reason for the swap. So does it matter that it came from a truck? Still a direct swap?
I have a '63 Dart with push button 904. I am not using a 63 crank.

Author:  Reed [ Thu Apr 25, 2019 1:06 pm ]
Post subject:  Re: ID this trans, 904 or some derivative?

The 81 904 will likely have more clutches than a car slant, a wide-ratio gearset, and it will be lockup. None of these are really a bad thing unless you are racing and don't like the larger RPM drop between 1st and second gears.

Author:  drgonzo [ Thu Apr 25, 2019 1:14 pm ]
Post subject:  Re: ID this trans, 904 or some derivative?

The numbers are:
4058383
http://mymopar.com/downloads/transguide.pdf

Author:  drgonzo [ Thu Apr 25, 2019 1:38 pm ]
Post subject:  Re: ID this trans, 904 or some derivative?

Is the rpm drop that significant? I am trying to build a relatively fast car so maybe I need to keep looking.

Author:  Badvert65 [ Thu Apr 25, 2019 1:55 pm ]
Post subject:  Re: ID this trans, 904 or some derivative?

According to Tom Hand's Torqueflite book, 4058383 is 1981 Dodge truck, 225, 904, wide ratio gear set, lock up converter.

Author:  Reed [ Thu Apr 25, 2019 2:16 pm ]
Post subject:  Re: ID this trans, 904 or some derivative?

drgonzo wrote:
Is the rpm drop that significant? I am trying to build a relatively fast car so maybe I need to keep looking.


Third gear is 1:1 in both the older narrow gear ratio and the later wide ratio gearset.

Wide ratio- 2.74, 1.54, 1
Close ratio- 2.45, 1.45, 1

Your can figure out what that means for your gearing and acceleration and what it means in relation to your power band.

Author:  drgonzo [ Thu Apr 25, 2019 3:23 pm ]
Post subject:  Re: ID this trans, 904 or some derivative?

I'm going to keep looking.

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