904??

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titanium

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Looking to replace my 904 tranny in my dart. My ? is are all years of 904 trannys the same? I have a 1967 now and I can get a 1984 that is out of a truck. Thanks
 
Around the late 70's to early '80's, transmissions started going to lock-up converters. They can be swapped in, but need to keep the transmission and converters together because they won't interchange with the "regular" ones. Lock-up transmissions have the tip of the splines machined back about 3/4' on the converter end.

Not sure if '66 or '67 was the last year for transmissions with a small converter "snout" that goes into the register at the back of the crank. Needless to say, the sizes don't interchange based on the crank.
 
Demon416 said:
Why not just rebuild what you have?
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I want to use mine. I bought a rebuilt 72 340(steel crank)and was just thinking that if I had another 904 I could just bolt it up to my new motor and take my motor/tranny out and put the new motor/tranny in. Hoping all in one afternoon. Figured it prob. would not work. Can any one recommend a good convertor and rebuild kit for those 904's? The 340 I have is pretty much a stock rebuild. The kit I was looking at was from Mancini(part # MREBMM904886). Not sure though.
 
If I remember correctly the 904's up to 72 had 23 splines on input shaft and 72 on had 24, there may be other differences, truck may have long tailshaft
 
I have a 67 904 and convertor that was behind a 273(small snout) I'd sell you
cheap($100) if you want to come over to Mass. to get it. Worked fine when I
pulled it out - I went with a newer - large spline 904 non-lock up and a 2400
stall convertor and put in a LA 360. Think they started using the large spline
904 non lock ups in 68. Also have the old 273 I'd sell also that ran when I took it
out - it's partially disassembled now but still good.
 
titanium said:
I want to use mine. I bought a rebuilt 72 340(steel crank)and was just thinking that if I had another 904 I could just bolt it up to my new motor and take my motor/tranny out and put the new motor/tranny in. Hoping all in one afternoon. Figured it prob. would not work. Can any one recommend a good convertor and rebuild kit for those 904's? The 340 I have is pretty much a stock rebuild. The kit I was looking at was from Mancini(part # MREBMM904886). Not sure though.
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Since your swapping to a newer engine you do need to swap to a 68 or newer 904 due to what Locomotion mentioned about the size of the register (snout) that slips into the crank. That size changed in 68. Just make sure you don't get a lockup trans. You can identify them easily by looking at the input shaft. If the first 3/8~1/2" of it is machined smooth it's a lockup trans. If the splines go all the way to the end it's a non lockup. I've used PTC converters with good results but there are several other manufacturers out there making good ones as well. Turbo Action, Ultimate, Dynamic, just to name a few. A good quality converter will cost you more than an off the shelf part but it'll perform better. Check out Trans Star rebuild kits. They are the same parts that Mancini (and others) repackage into their boxes and charge more for. Northern Auto parts has good prices on them. Also check into installing a Trans-go TF-1 or TF-2 shift improver kit. It'll make the trans. last a lot longer and work better.
 
this shows the two different input shafts...
 

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Thank you! O.K. gotta look for a newer 904. Figured it wouldn't be that easy. There is a gentleman that has a 84 904 out of a truck for sale locally. Would that mite be the correct model 904 I would be looking for? I will check on those convertors you mentioned. I would like to collect all these parts before fall and drop it in.
 
i have a 78 lock up which means it has an over drive in my car,so the 84 will probably be a lock up.I assume it is a 2 wheel drive if it is a factory tranny for the truck,most trucks have the 727.make sure what your getting the 727 will bolt up also and is stronger but carries more turning wieght.i like the idea of having the over drive as long as it holds up to the power.I'm no tranny expert but I assume you can get a stall for them just make sure they know what it is if you buy.
 
Lockup and overdrive are not the same. A lockup simply locks up the torque converter down the hwy so it doesn't slip any. It only drops the rpm 100-200 rpm at the very most. Overdrive is a complete other gearset and will drop the rpm several hundred. They also made lockup and non lockup trans. all throught the yrs so it can go either way. You are correct that most truck trans. are 727's.
 
fishy68 said:
Lockup and overdrive are not the same. A lockup simply locks up the torque converter down the hwy so it doesn't slip any. It only drops the rpm 100-200 rpm at the very most. Overdrive is a complete other gearset and will drop the rpm several hundred. They also made lockup and non lockup trans. all throught the yrs so it can go either way. You are correct that most truck trans. are 727's.
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Cool.I have the lock up and I guess the info I got about it was "sketchy".Thanks for clearing that up.
 
Again thank you. Well now I know what I need to get. There are a few for sale locally so just gotta go and see which one I need and buy one.
 
O. K. I have another question. If I went with a 727 trans instead of, my 904,would my shift (column shift)linkage hook up the same as it would to my original 904?
Thanks
 
titanium said:
O. K. I have another question. If I went with a 727 trans instead of, my 904,would my shift (column shift)linkage hook up the same as it would to my original 904?
Thanks
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no, you may be able to use the cross shaft and the lever, but the rest is different. also the kickdown(throttle pressure) linkage may not work properly. unless you have acess to all the little parts that are all but obsolete, stay with what you have. theres nothing wrong with a well built 904.
 
I have one more question. How would you tell what year 904 it is? Are they like the blocks having the year on them?
Thanks
 
on the driver side...just above the pan mounting surface ..there is a number stamped ...starts with a PK

then has a bunch of numbers....then look here

[ame]http://mymopar.com/downloads/transguide.pdf[/ame]
 
There are also heavy duty parts available for the 904. Like heavy duty clutches and stuff. If you use them, It will hold up much better than just a stock rebuild. With those heavy duty parts, it should hold up to the 340.
 
Thanks again. Going to look at two 904's tomorrow morning and just wanted to make sure I'm looking for the right year.
 
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